Hash table/Collection

How do you translate a hash table to a collection? Specifically with the Vector class.

That question doesn't really make sense. You can easily take data in a hashtable and put it in a subclass of Collection, but how one does so, or whether it's appropriate, is doing to depend on the situation. There isn't a "this is how you do it" answer to this.
By the way, Hashtables are a collection, in the sense of being part of the Collections Framework, although not in the sense of being a subclass of Collection.

Similar Messages

Collection MAP HASh map hash table

Hi
i wan to be familiar with Collection MAP API hasp map & hash table
please guide me...
tell me resource link where i can get more information about it.
Bunty

Thanks Jos
it is more theortical You just skimmed through it for at most eleven minutes. How can you
tell it's 'more theoretical'? It is a tutorial you know ...
kind regards,
Jos

Comparing String values against a collection of Names in a Hash Table

Objective:
Is to make a script that will import a csv file containing two values: "Name" and "Price". This would ideally be stored in a hash table with the key name of "Name" and the value being "Price". The second part would be
importing a second csv file that has a list of names to compare too. If it finds a similar match to a key name in the hash table and then it will add that to a new array with the price. At the end it would add all the prices and give you a total value.
The Problem to Solve:
In the real world people have a tendency to not write names exactly the same way, for example I am looking at a list of books to buy in an eBay auction. In the auction they provide a text list of all the names of books for sale. In my price guide it has all
the names and dollar values of each book. The wording of the way each book is named could differ from the person who writes it and what is actually in my reference pricing list. An example might be "The Black Sheep" vs "Black Sheep" or
"Moby-Dick" vs "Moby Dick".
I've tried making a script and comparing these values using the -like operator and have only had about 70% accuracy. Is there a way to increase that by
comparing the characters instead of likeness of words? I'm not really sure how to solve this issue as it's very hard to do quality check on the input when your talking about hundreds of names in the list. Is there a better way to compare values in power-shell
then the "like" operator? Do I need to use a database instead of a hash table? In the real world I feel like a search engine would know the differences in these variations and still provide the desired results so why not for this type of application?
In other words, create a bit more intelligence to say well it's not a 100% match but 90% so that is close enough, add it to the array as a match and add the price etc..
I'd be curious as to any thoughts on this? Maybe a scripting language with better matching for text?

Have you considered setting up a manual correction process that "learns" as you make corrections, automatically building a look up table of possible spellings of each Name? If you get an exact match, use it. If not, go to the look up
table and see if there's been a previous entry with the same spelling and what it was corrected to.
[string](0..33|%{[char][int](46+("686552495351636652556262185355647068516270555358646562655775 0645570").substring(($_*2),2))})-replace " "

How to Implement a Chained Hash Table with Linked Lists

I'm making a migration from C/C++ to Java, and my task is to implement a Chained Hash Table with a Linked List. My problem is to put the strings(in this case names) hashed by the table using de Division Metod (H(k)= k mod N) in to a Linked list that is handling the colisions. My table has an interface implemented(public boolean insert(), public boolean findItem(), public void remove()). Any Help is needed. Thanks for everyone in advance.

OK. you have your hash table. What you want it to do is keep key/value pairs in linked lists, so that when there is a collision, you add the key/value pair to the linked list rather than searching for free space on the table.
This means that whenever you add an item, you hash it out, check to see if there is already a linked list and if not, create one and put it in that slot. Then in either case you add the key/value pair to the linked list if the key is not already on the linked list. If it is there you have to decide whether your requirements are to give an error or allow duplicate keys or just keep or modify one or the other (old/new).
When you are searching for a key, you hash it out once again and check to see if there is a linked list at that slot. If there is one, look for the key and if it's there, return it and if not, or if there was no linked list at that slot, return an error.
You aren't clear on whether you can simply use the provided linked-list implementations in the Java Collections or whether you have to cobble the linked list yourself. In any case, it's up to you.
Is this what you're asking?
Doug

How to store a text file in a hash table in C#?

I am fairly new to c#. I am creating a console application project for practice. I am supposed to create a program that reads a text file (it's a poem), store it in a hash table, have two different sorts, and unhash the table. I managed to get the poem read
by using streamwriter, but now I am not sure how to store it in a hash table.
I'm not sure if I am doing this hash table correct, but I made my hash table like this to store the text file:
Hashtable hashtable = new Hashtable();
hashtable[1] = (@"C:\\Documents\\Datastructures\\Input\\Poem");

Hi,
Hashtable in C# represents a collection of key/value pairs which maps keys to value. Any non-null object can be used as a key but a value can. We can retrieve items from hashTable to provide the key . Both keys and values are Objects.
Here is a sample about Hashtable,
Hashtable weeks = new Hashtable();
weeks.Add("1", "SunDay");
weeks.Add("2", "MonDay");
weeks.Add("3", "TueDay");
weeks.Add("4", "WedDay");
weeks.Add("5", "ThuDay");
weeks.Add("6", "FriDay");
weeks.Add("7", "SatDay");
//Display a single Item
MessageBox.Show(weeks["5"].ToString());
//Search an Item
if (weeks.ContainsValue("TueDay"))
MessageBox.Show("Find");
else
MessageBox.Show("Not find");
//remove an Item
weeks.Remove("3");
//Display all key value pairs
foreach (DictionaryEntry day in weeks)
MessageBox.Show(day.Key + " - " + day.Value);
>>I managed to get the poem read by using streamwriter, but now I am not sure how to store it in a hash table
Hashtable hashtable = new Hashtable();
hashtable[1] = (@"C:\\Documents\\Datastructures\\Input\\Poem");
But follow your scenario above, you just store a string path to hashtable not a file.
About saving data to a file, you can use the following code.
// Write the string to a file.
System.IO.StreamWriter file = new System.IO.StreamWriter("c:\\test.txt");
file.WriteLine(lines);
file.Close();
Best wishes!
Kristin
We are trying to better understand customer views on social support experience, so your participation in this interview project would be greatly appreciated if you have time. Thanks for helping make community forums a great place.
Click
HERE to participate the survey.

How to create hashed table in runtime

hi experts
how to create hashed table in runtime, please give me the coading style.
please help me.
regards
subhasis

Hi,
Have alook at the code, and pls reward points.
Use Hashed Tables to Improve Performance :
report zuseofhashedtables.
Program: ZUseOfHashedTables **
Author: XXXXXXXXXXXXXXXXXX **
Versions: 4.6b - 4.6c **
Notes: **
 this program shows how we can use hashed tables to improve **
 the responce time. **
 It shows, **
 1. how to declare hashed tables **
 2. a cache-like technique to improve access to master data **
 3. how to collect data using hashed tables **
 4. how to avoid deletions of unwanted data **
Results: the test we run read about 31000 rows from mkpf, 150000 **
 rows from mseg, 500 rows from makt and 400 from lfa1. **
 it filled ht_lst with 24500 rows and displayed them in **
 alv grid format. **
 It needed about 65 seconds to perform this task (with **
 all the db buffers empty) **
 The same program with standard tables needed 140 seconds **
 to run with the same recordset and with buffers filled in **
Objetive: show a list that consists of all the material movements **
 '101' - '901' for a certain range of dates in mkpf-budat. **
the columns to be displayed are: **
 mkpf-budat, **
 mkpf-mblnr, **
 mseg-lifnr, **
 lfa1-name1, **
 mkpf-xblnr, **
 mseg-zeile **
 mseg-charg, **
 mseg-matnr, **
 makt-maktx, **
 mseg-erfmg, **
 mseg-erfme. **
or show a sumary list by matnr - menge **
You'll have to create a pf-status called vista - **
See form set_pf_status for details **
tables used -
tables: mkpf,
 mseg,
 lfa1,
 makt.
global hashed tables used
data: begin of wa_mkpf, "header
 mblnr like mkpf-mblnr,
 mjahr like mkpf-mjahr,
 budat like mkpf-budat,
 xblnr like mkpf-xblnr,
 end of wa_mkpf.
data: ht_mkpf like hashed table of wa_mkpf
 with unique key mblnr mjahr
 with header line.
data: begin of wa_mseg, " line items
 mblnr like mseg-mblnr,
 mjahr like mseg-mjahr,
 zeile like mseg-zeile,
 bwart like mseg-bwart,
 charg like mseg-charg,
 matnr like mseg-matnr,
 lifnr like mseg-lifnr,
 erfmg like mseg-erfmg,
 erfme like mseg-erfme,
 end of wa_mseg.
data ht_mseg like hashed table of wa_mseg
 with unique key mblnr mjahr zeile
 with header line.
cache structure for lfa1 records
data: begin of wa_lfa1,
 lifnr like lfa1-lifnr,
 name1 like lfa1-name1,
 end of wa_lfa1.
data ht_lfa1 like hashed table of wa_lfa1
 with unique key lifnr
 with header line.
cache structure for material related data
data: begin of wa_material,
 matnr like makt-matnr,
 maktx like makt-maktx,
 end of wa_material.
data: ht_material like hashed table of wa_material
 with unique key matnr
 with header line.
result table
data: begin of wa_lst, "
 budat like mkpf-budat,
 mblnr like mseg-mblnr,
 lifnr like mseg-lifnr,
 name1 like lfa1-name1,
 xblnr like mkpf-xblnr,
 zeile like mseg-zeile,
 charg like mseg-charg,
 matnr like mseg-matnr,
 maktx like makt-maktx,
 erfmg like mseg-erfmg,
 erfme like mseg-erfme,
 mjahr like mseg-mjahr,
 end of wa_lst.
data: ht_lst like hashed table of wa_lst
 with unique key mblnr mjahr zeile
 with header line.
data: begin of wa_lst1, " sumary by material
 matnr like mseg-matnr,
 maktx like makt-maktx,
 erfmg like mseg-erfmg,
 erfme like mseg-erfme,
 end of wa_lst1.
data: ht_lst1 like hashed table of wa_lst1
 with unique key matnr
 with header line.
structures for alv grid display.
itabs
type-pools: slis.
data: it_lst like standard table of wa_lst with header line,
 it_fieldcat_lst type slis_t_fieldcat_alv with header line,
 it_sort_lst type slis_t_sortinfo_alv,
 it_lst1 like standard table of wa_lst1 with header line,
 it_fieldcat_lst1 type slis_t_fieldcat_alv with header line,
 it_sort_lst1 type slis_t_sortinfo_alv.
structures
data: wa_sort type slis_sortinfo_alv,
 ls_layout type slis_layout_alv.
global varialbes
data: g_lines type i.
data: g_repid like sy-repid,
 ok_code like sy-ucomm.
selection-screen
"text: Dates:
select-options: so_budat for mkpf-budat default sy-datum.
"text: Material numbers.
select-options: so_matnr for mseg-matnr.
selection-screen uline.
selection-screen skip 1.
"Text: show summary by material.
parameters: gp_bymat as checkbox default ''.
start-of-selection.
perform get_data.
perform show_data.
end-of-selection.
 FORM get_data *
form get_data.
 select mblnr mjahr budat xblnr
 into table ht_mkpf
 from mkpf
 where budat in so_budat. " make use of std index.
have we retrieved data from mkpf?
describe table ht_mkpf lines g_lines.
if g_lines > 0.
if true then retrieve all related records from mseg.
Doing this way we make sure that the access is by primary key
of mseg.
The reason is that is faster to filter them in memory
than to allow the db server to do it.
 select mblnr mjahr zeile bwart charg
 matnr lifnr erfmg erfme
 into table ht_mseg
 from mseg
 for all entries in ht_mkpf
 where mblnr = ht_mkpf-mblnr
 and mjahr = ht_mkpf-mjahr.
endif.
fill t_lst or t_lst1 according to user's choice.
if gp_bymat = ' '.
 perform fill_ht_lst.
else.
 perform fill_ht_lst1.
endif.
endform.
form fill_ht_lst.
refresh ht_lst.
Example: how to discard unwanted data in an efficient way.
loop at ht_mseg.
filter unwanted data
 check ht_mseg-bwart = '101' or ht_mseg-bwart = '901'.
 check ht_mseg-matnr in so_matnr.
read header line.
 read table ht_mkpf with table key mblnr = ht_mseg-mblnr
 mjahr = ht_mseg-mjahr.
 clear ht_lst.
* note : this may be faster if you specify field by field.
 move-corresponding ht_mkpf to ht_lst.
 move-corresponding ht_mseg to ht_lst.
 perform read_lfa1 using ht_mseg-lifnr changing ht_lst-name1.
 perform read_material using ht_mseg-matnr changing ht_lst-maktx.
 insert table ht_lst.
endloop.
endform.
form fill_ht_lst1.
refresh ht_lst1.
Example: how to discard unwanted data in an efficient way.
 hot to simulate a collect in a faster way
loop at ht_mseg.
filter unwanted data
 check ht_mseg-bwart = '101' or ht_mseg-bwart = '901'.
 check ht_mseg-matnr in so_matnr.
* note : this may be faster if you specify field by field.
 read table ht_lst1 with table key matnr = ht_mseg-matnr
 transporting erfmg.
 if sy-subrc <> 0. " if matnr doesn't exist in sumary table
 " insert a new record
 ht_lst1-matnr = ht_mseg-matnr.
 perform read_material using ht_mseg-matnr changing ht_lst1-maktx.
 ht_lst1-erfmg = ht_mseg-erfmg.
 ht_lst1-erfme = ht_mseg-erfme.
 insert table ht_lst1.
 else." a record was found.
 " collect erfmg. To do so, fill in the unique key and add
 " the numeric fields.
 ht_lst1-matnr = ht_mseg-matnr.
 add ht_mseg-erfmg to ht_lst1-erfmg.
 modify table ht_lst1 transporting erfmg.
 endif.
endloop.
endform.
implementation of cache for lfa1.
form read_lfa1 using p_lifnr changing p_name1.
 read table ht_lfa1 with table key lifnr = p_lifnr
 transporting name1.
if sy-subrc <> 0.
 clear ht_lfa1.
 ht_lfa1-lifnr = p_lifnr.
 select single name1
 into ht_lfa1-name1
 from lfa1
 where lifnr = p_lifnr.
 if sy-subrc <> 0. ht_lfa1-name1 = 'n/a in lfa1'. endif.
 insert table ht_lfa1.
endif.
p_name1 = ht_lfa1-name1.
endform.
implementation of cache for material data
form read_material using p_matnr changing p_maktx.
read table ht_material with table key matnr = p_matnr
transporting maktx.
if sy-subrc <> 0.
 ht_material-matnr = p_matnr.
 select single maktx into ht_material-maktx
 from makt
 where spras = sy-langu
 and matnr = p_matnr.
 if sy-subrc <> 0. ht_material-maktx = 'n/a in makt'. endif.
 insert table ht_material.
endif.
p_maktx = ht_material-maktx.
endform.
form show_data.
if gp_bymat = ' '.
 perform show_ht_lst.
else.
 perform show_ht_lst1.
endif.
endform.
form show_ht_lst.
"needed because the FM can't use a hashed table.
it_lst[] = ht_lst[].
perform fill_layout using 'full display'
 changing ls_layout.
perform fill_columns_lst.
perform sort_lst.
g_repid = sy-repid.
call function 'REUSE_ALV_GRID_DISPLAY'
 exporting
 i_callback_program = g_repid
 i_callback_pf_status_set = 'SET_PF_STATUS'
 is_layout = ls_layout
 it_fieldcat = it_fieldcat_lst[]
 it_sort = it_sort_lst
 tables
 t_outtab = it_lst
 exceptions
 program_error = 1
 others = 2.
endform.
form show_ht_lst1.
"needed because the FM can't use a hashed table.
it_lst1[] = ht_lst1[].
perform fill_layout using 'Sumary by matnr'
 changing ls_layout.
perform fill_columns_lst1.
perform sort_lst.
g_repid = sy-repid.
call function 'REUSE_ALV_GRID_DISPLAY'
 exporting
 i_callback_program = g_repid
 i_callback_pf_status_set = 'SET_PF_STATUS'
 is_layout = ls_layout
 it_fieldcat = it_fieldcat_lst1[]
 it_sort = it_sort_lst
 tables
 t_outtab = it_lst1
 exceptions
 program_error = 1
 others = 2.
endform.
form fill_layout using p_window_titlebar
 changing cs_layo type slis_layout_alv.
clear cs_layo.
cs_layo-window_titlebar = p_window_titlebar.
cs_layo-edit = 'X'.
cs_layo-edit_mode = space.
endform. " armar_layout_stock
form set_pf_status using rt_extab type slis_t_extab.
create a new status
and then select extras -> adjust template -> listviewer
set pf-status 'VISTA'.
endform. "set_pf_status
define add_lst.
clear it_fieldcat_lst.
it_fieldcat_lst-fieldname = &1.
it_fieldcat_lst-outputlen = &2.
it_fieldcat_lst-ddictxt = 'L'.
it_fieldcat_lst-seltext_l = &1.
it_fieldcat_lst-seltext_m = &1.
it_fieldcat_lst-seltext_m = &1.
if &1 = 'MATNR'.
 it_fieldcat_lst-emphasize = 'C111'.
endif.
append it_fieldcat_lst.
end-of-definition.
define add_lst1.
clear it_fieldcat_lst.
it_fieldcat_lst1-fieldname = &1.
it_fieldcat_lst1-outputlen = &2.
it_fieldcat_lst1-ddictxt = 'L'.
it_fieldcat_lst1-seltext_l = &1.
it_fieldcat_lst1-seltext_m = &1.
it_fieldcat_lst1-seltext_m = &1.
append it_fieldcat_lst1.
end-of-definition.
form fill_columns_lst.
set columns for output.
refresh it_fieldcat_lst.
add_lst 'BUDAT' 10.
add_lst 'MBLNR' 10.
add_lst 'LIFNR' 10.
add_lst 'NAME1' 35.
add_lst 'XBLNR' 15.
add_lst 'ZEILE' 5.
add_lst 'CHARG' 10.
add_lst 'MATNR' 18.
add_lst 'MAKTX' 30.
add_lst 'ERFMG' 17.
add_lst 'ERFME' 5.
add_lst 'MJAHR' 4.
endform.
form fill_columns_lst1.
set columns for output.
refresh it_fieldcat_lst1.
add_lst1 'MATNR' 18.
add_lst1 'MAKTX' 30.
add_lst1 'ERFMG' 17.
add_lst1 'ERFME' 5..
endform.
Regards,
Ameet

Creating hash table with more than two columns

Hello,
I tried to search around and can't quite find what I'm trying to do. I know I can make a hash table like:
$Hash = @{"Texas" = "Hot";"Alaska" = "Cold"}
But I would like to add a third column, so for the sake of an example have the third one say travel by air and the other travel by car. What's the syntax so I can add more columns than two? Also, how can I change the column header names?

I think you want something more like this:
New-Object PSObject -property @{
State="Texas"
Temp="Hot"
Travel="Air"
If I set $hash to equal that:
$hash = New-Object PSObject -property @{State="Texas";Temp="Hot";Travel="Air"}
I get this:
Travel Temp State
Air Hot
Texas
If I have a master variable
$hashes = @()
I can set $hash to the new-object of relevant values each pass of a loop:
$hash = New-Object PSObject -property @{State="Alaska";Temp="Cold";Travel="Car"}
And add that to $hashes each time:
$hashes += $hash
and add to the collection:
Travel Temp State
Air Hot
Texas
Car Cold Alaska
As mjolinor suggested, you really need to understand what you want to do. I suspect you are just unfamiliar with the terms, because what you're describing is an array of values, which is better suited to a PSObject rather than to a hash table.
The method for populating a PSObject I describe above is just one variation of one particular method for doing so, there are others that may be more or less suitable for what you want to do.
I hope this post has helped!
Thank you, this is what I was looking for. I've never had to use powershell for this type of task before and did know of this process, and only could find hash tables when I poked around. This will make life much easier!

Header, Line Item and Cache Techniques Using Hashed Tables

Hi,
How can I work with header, line item, and a cache techniques using hashed tables?
Thanks,
Shah.

Hi,
Here is an example to clarify the ideas:
In general, every time you have a header-> lines structure you have a unique key for the lines that has at least header key plus one or more fields. I'll make use of this fact.
I'll try to put an example of how to work with header -> line items and a cache technique using hashed tables.
Just suppose that you need a list of all the material movements '101'-'901' for a certain range of dates in mkpf-budat. We'll extract these fields:
mkpf-budat
mkpf-mblnr,
mseg-lifnr,
lfa1-name1,
mkpf-xblnr,
mseg-zeile
mseg-charg,
mseg-matnr,
makt-maktx,
mseg-erfmg,
mseg-erfme.
I'll use two cache: one for maintaining lfa1 related data and the other to maintain makt related data. Also I'll only describe the data gathering part. The showing of the data is left to your own imagination.
The main ideas are:
1. As this is an example I won't use inner join. If properly desingned may be faster .
2. I'll use four hashed tables: ht_mkpf, ht_mseg, ht_lfa1 and ht_makt to get data into memory. Then I'll collect all the data I want to list into a fifth table ht_lst.
3. ht_mkpf should have (at least) mkpf's primary key fields : mjahr, mblnr.
4. ht_mseg should have (at least) mseg primary key fields: mjahr mblnr and zeile.
5. ht_lfa1 should have an unique key by lifnr.
6. ht_makt should have an unique key by matnr.
7. I prefer using with header line because makes the code easier to follow and understand. The waste of time isn't quite significant (in my experience at least).
Note: When I've needed to work from header to item lines then I added a counter in ht_header that maintains the count of item lines, and I added an id in the ht_lines so I can read straight by key a given item line. But this is very tricky to implement and to follow. (Nevertheless I've programmed it and it works well.)
The data will be read in this sequence:
select data from mkpf into table ht_mkpf
select data from mseg int table ht_mseg having in count all the data in ht_mkpf
loop at ht_mseg (lines)
filter unwanted records
read cache for lfa1 and makt
fill in ht_lst and collect data
endloop.
tables
tables: mkpf, mseg, lfa1, makt.
internal tables:
data: begin of wa_mkpf, "header
mblnr like mkpf-mblnr,
mjahr like mkpf-mjahr,
budat like mkpf-budat,
xblnr like mkpf-xblnr,
end of wa_mkpf.
data ht_mkpf like hashed table of wa_mkpf
with unique key mblnr mjahr
with header line.
data: begin of wa_mseg, " line items
mblnr like mseg-mblnr,
mjahr like mseg-mjahr,
zeile like mseg-zeile,
bwart like mseg-bwart,
charg like mseg-charg,
matnr like mseg-matnr,
lifnr like mseg-lifnr,
erfmg like mseg-erfmg,
erfme like mseg-erfme,
end of wa_mseg,
data ht_mseg like hashed table of wa_mseg
with unique key mblnr mjahr zeile
with header line.
data: begin of wa_lfa1,
lifnr like lfa1-lifnr,
name1 like lfa1-name1,
end of wa_lfa1,
data ht_lfa1 like hashed table of wa_lfa1
with unique key lifnr
with header line.
data: begin of wa_makt,
matnr like makt-matnr,
maktx like makt-maktx,
end of wa_makt.
data: ht_makt like hashed table of wa_makt
with unique key matnr
with header line.
result table
data: begin of wa_lst, "
budat like mkpf-budat,
mblnr like mseg-mblnr,
lifnr like mseg-lifnr,
name1 like lfa1-name1,
xblnr like mkpf-xblnr,
zeile like mseg-zeile,
charg like mseg-charg,
matnr like mseg-matnr,
maktx like makt-maktx,
erfmg like mseg-erfmg,
erfme like mseg-erfme,
mjahr like mseg-mjahr,
end of wa_mseg,
data: ht_lst like hashed table of wa_lst
with unique key mblnr mjahr zeile
with header line.
data: g_lines type i.
select-options: so_budat for mkpf-budat default sy-datum.
select-options: so_matnr for mseg-matnr.
form get_data.
select mblnr mjahr budat xblnr
into table ht_mkfp
from mkpf
where budat in so_budat.
describe table ht_mkpf lines g_lines.
if lines > 0.
select mblnr mjahr zeile bwart charg
matnr lifnr erfmg erfme
into table ht_mseg
from mseg
for all entries in ht_mkpf
where mblnr = ht_mkpf-mblnr
and mjahr = ht_mjahr.
endif.
loop at ht_mseg.
filter unwanted data
check ht_mseg-bwart = '101' or ht_mseg-bwart = '901'.
check ht_mseg-matnr in so_matnr.
read header line.
read table ht_mkpf with table key mblnr = ht_mseg-mblnr
mjahr = ht_mseg-mjahr.
clear ht_lst.
note : this may be faster if you specify field by field.
move-corresponding ht_mkpf to ht_lst.
move-corresponding ht_mseg to ht_lst.
perform read_lfa1 using ht_mseg-lifnr changing ht_lst-name1.
perform read_makt using ht_mseg-matnr changing ht_lst-maktx.
insert table ht_lst.
endloop.
implementation of cache for lfa1.
form read_lfa1 using p_lifnr changing p_name1.
read table ht_lfa1 with table key lifnr = p_lifnr
transporting name1.
if sy-subrc <> 0.
clear ht_lfa1.
ht_lfa1-lifnr = p_lifnr.
select single name1
into ht_lfa1-name1
from lfa1
where lifnr = p_lifnr.
if sy-subrc <> 0. ht_lfa1-name1 = 'n/a in lfa1'. endif.
insert table ht_lfa1.
endif.
p_name1 = ht_lfa1-name1.
endform.
implementation of cache for makt
form read_makt using p_matnr changing p_maktx.
read table ht_makt with table key matnr = p_matnr
transporting maktx.
if sy-subrc <> 0.
ht_makt-matnr = p_matnr.
select single maktx into ht_matk-maktx
from makt
where spras = sy-langu
and matnr = p_matnr.
if sy-subrc <> 0. ht_makt-maktx = 'n/a in makt'. endif.
insert table ht_makt.
endif.
p_maktx = ht_makt-maktx.
endform.
Reward points if found helpfull...
Cheers,
Siva.

URGENT - Sorting Hash Tables

I am using a hash table with 2 columns. The first one has strings and is the key. The second column has integers.
I need to sort this table on the first column and print the contents of the table.
Then i need to sort it on the second column and print the results.
How do i sort the hastables.
Please let me know as soon as possible.
Thanks and Regards,
Vijay

You got it all wrong. Hashtables cannot be sorted because then it would not be a hashtable. The content of the Hashtable can be sorted.
What you want to do is get the key Set (keySet() method) of the Hashtable, wrap it in a List (e.g. LinkedList), sort that (see java.util.Collections for sorting) and then print out the contents of the Hashtable in the order pointed out by the keys in the sorted List.
Then you can do the same for the values() Collection of the Hashtable.
Pointers:
http://java.sun.com/j2se/1.4/docs/api/java/util/Hashtable.html
http://java.sun.com/j2se/1.4/docs/api/java/util/Set.html
http://java.sun.com/j2se/1.4/docs/api/java/util/List.html
http://java.sun.com/j2se/1.4/docs/api/java/util/LinkedList.html
http://java.sun.com/j2se/1.4/docs/api/java/util/Collections.html

Sort Multiple Times on Hash Table

I have a hash table that the key is id, value is a string of first name, last name, and age.
for example:
Hashtable showHT = new Hashtable();
showHT.put(person.getId(), person); <--- person is an object that contains all information
How to do sorting?
If I want to sort by id, last name, first name, and age, how can I do it.
I just know how to do once:
for exmpale, sorting by id:
Vector v = new Vector(showHT.keySet());
Collections.sort(v);
for (int i = 0; i < v.size(); i++)
 Integer key = (Integer) v.get(i);
 String str = (String) showHT.get(key).toString();
 out.println(key + ": " + str);
}How can I do the sorting by id, last name, first name, and age?
Thank you.

Given your "design", it is trivial to sort by id -- use a TreeMap .
Beyond that, you're going to have to face a basic fact: your design sucks. You are abusing Strings.
You need to:
1. Define a Person class
2. Define multiple Person Comparators
At that point you are essentially done.
[http://java.sun.com/docs/books/tutorial/collections/algorithms/index.html#sorting]
edit: or did I misread your vague code snippet? What type is person?

Implementing a threaded Hash Table

Hiya all,
Would like to know how to create a threaded hash table. I am making a program that should be able to take in different variables such as string and integers, and be able to store then in a Hash table. Would it be possible to retreive these variables (remove them from the hash map) in a threaded scenario?

Unlike the new collection implementations, Hashtable
is synchronized.True, but HashMap is more stable. Its performance stays roughtly the same when it's loaded with different (biased) data sets whereas Hashtable shows much more variation.

Re: Hash table usage

The Born collection classes don't have an alternative implementation of
HashTable. Instead they are wrappers around the Forté Framework classes
using Array, HashTable etc.
Raymond Blum wrote:
>
Eric
Although I have not looked at them in a while, I remember the Born
Collection Classes having some HashTable and Iterator functionality that
might be worth looking at as an alternative.
The last version I had is 1.2 and was offered under the GNU license,
there may be something newer, check out
http://www.born.com
or email
[email protected]
On Thu, 6 May 1999, Fingerhut, Eric wrote:
We have been using the hashtable class in our application, and have recently
hit performance problems that lead us to the following questions:
1) Forte's hashing algorithm - we are concerned that Forte's hashing
algorithm may not be ideal or even adequate for our data; does anyone know
how it works?
2) Hash table performance - any ideas on how to guage it?
3) Is anyone aware of a binary tree implementation that might be
available?
Dr. Thomas Kunst mailto:[email protected]
sd&m GmbH & Co. KG http://www.sdm.de
software design & management
Thomas-Dehler-Str. 27, 81737 Muenchen, Germany
Tel +49 89 63812-221 Fax -444
To unsubscribe, email '[email protected]' with
'unsubscribe forte-users' as the body of the message.
Searchable thread archive <URL:http://pinehurst.sageit.com/listarchive/>

I'm trying to understand what you have and what you are trying to do. First of all, the Web PL/SQL generator requires you to generate Table APIs (TAPIs) for every table referenced in a module component. If you created one based on a view, the only way to get it to work is to generate a TAPI on the view, which Designer doesn't do natively. I've fooled Designer into generating a view TAPI by creating a table definition that looks exactly like the view and has the same name, and generating the TAPI for that table. Even then, I have to hand-modify the resulting TAPI to remove references to ROWID, since views don't have rowids.
I've never tried generating TAPI against a materialized view (MV) - it might work, since there really is a table to instantiate the MV, but it might require the same work around as the view.
As for the reference in the module component definition, I think you have to delete the old table reference and create a new one. I'm not sure what you are doing with "copy object". Remapping is usually done when you are copying an object from one application system to another, and want the references to point at equivalent objects in the new application system, not the objects in the old one.

Implementing Hash tables with chaining.

Hi, I'm in a Java data structures class right now and we have a program to do using hash tables. I've read about hash tables and chaining but does anyone know where i can find some examples of code that implement hash tables using chaining. It's all very confusing to me without seeing how it is used in a program.
To give you an idea of what we're doing, the assignment is to create a word processor that looks thru a file and adds different words to the table and also counts how many of each word there is in that file. Keep in mind I'm not asking for the code to this assignment just for some example of how coding hash tables/chaining works.

Simple and probably not complete overview:
Suppose you have an array in which you will store objects.
You take an object, and find a "hash code" for it. You then restrict the hash code in to the range of your array. This gives you the index where you can store your object.
But what if another object is already present at that index?
Different solutions to this exist - such as re-hashing. One solution is "chaining". Instead of storing the object directly at the hashed index - you store a list of objects which hashed to the same location.
When you do a lookup, you first get your hash. You then look at the corresponding location in the array. If you find a list rather than the required object, you walk along the list until you find the object you are looking for.
Of course, with a small array and bad hash distribution, the performance of this solution can degrade fairly quickly.
BTW, in the real world, just use one of the ready made collections in java.util.

Question about sorted, hashed tables, mindset when using OO concepts...

Hello experts,
I just want to make sure if my idea about sorted and hashed table is correct.Please give tips and suggestions.
In one of my reports, I declared a structure and an itab.
TYPES: BEGIN OF t_mkpf,
 mblnr LIKE mkpf-mblnr,
 mjahr LIKE mkpf-mjahr,
 budat LIKE mkpf-budat,
 xblnr(10) TYPE c,
 tcode2 LIKE mkpf-tcode2,
 cputm LIKE mkpf-cputm,
 blart LIKE mkpf-blart,
 END OF t_mkpf.
it_mkpf TYPE SORTED TABLE OF t_mkpf WITH HEADER LINE
 WITH NON-UNIQUE KEY mblnr mjahr.
Now, I declared it as a sorted table with a non-unique key MBLNR and MJAHR. Now suppose I have 1000 records in my itab. how will it search for a particular record?
2. Is it faster than sorting a standard table then reading it using binary search?
3. How do I use a hashed table effectively? lets say that I want to use hashed type instead of sorted table in my example above.
4. I am currently practicing ABAP Objects and my problem is that I think my mindset when programming a report is still the 'procedural one'. How do one use ABAP concepts effectively?
Again, thank you guys and have a nice day!

Hi Viray,
The different ways to fill an Internal Table:
append&sort
This is the simplest one. I do appends on a standard table and then a sort.
data: lt_tab type standard table of ...
do n times.
ls_line = ...
append ls_line to lt_tab.
enddo.
sort lt_tab.
The thing here is the fast appends and the slow sort - so this is interesting how this will compare to the following one.
read binary search & insert index sy-tabix
In this type I also use a standard table, but I read to find the correct insert index to get a sorted table also.
data: lt_tab type standard table of ...
do n times.
ls_line = ...
read table lt_tab transporting no fields with key ... binary search.
if sy-subrc <> 0.
insert ls_line into lt_tab index sy-tabix.
endif.
enddo.
sorted table with non-unique key
Here I used a sorted table with a non-unique key and did inserts...
data: lt_tab type sorted table of ... with non-unique key ...
do n times.
ls_line = ...
insert ls_line into table lt_tab.
enddo.
sorted table with unique key
The coding is the same instead the sorted table is with a unique key.
data: lt_tab type sorted table of ... with unique key ...
do n times.
ls_line = ...
insert ls_line into table lt_tab.
enddo.
hashed table
The last one is the hashed table (always with unique key).
data: lt_tab type hashed table of ... with unique key ...
do n times.
ls_line = ...
insert ls_line into table lt_tab.
enddo.
You Can use this Program to Test:
types:
begin of local_long,
 key1 type char10,
 key2 type char10,
 data1 type char10,
 data2 type char10,
 data3 type i,
 data4 type sydatum,
 data5 type numc10,
 data6 type char32,
 data7 type i,
 data8 type sydatum,
 data9 type numc10,
 dataa type char32,
 datab type i,
 datac type sydatum,
 datad type numc10,
 datae type char32,
 dataf type i,
 datag type sydatum,
 datah type numc10,
 datai type char32,
 dataj type i,
 datak type sydatum,
 datal type numc10,
 datam type char32,
 datan type i,
 datao type sydatum,
 datap type numc10,
 dataq type char32,
 datar type i,
 datas type sydatum,
 datat type numc10,
 datau type char32,
 datav type i,
 dataw type sydatum,
 datax type numc10,
 datay type char32,
 dataz type i,
 data11 type numc10,
 data21 type char32,
 data31 type i,
 data41 type sydatum,
 data51 type numc10,
 data61 type char32,
 data71 type i,
 data81 type sydatum,
 data91 type numc10,
 dataa1 type char32,
 datab1 type i,
 datac1 type sydatum,
 datad1 type numc10,
 datae1 type char32,
 dataf1 type i,
 datag1 type sydatum,
 datah1 type numc10,
 datai1 type char32,
 dataj1 type i,
 datak1 type sydatum,
 datal1 type numc10,
 datam1 type char32,
 datan1 type i,
 datao1 type sydatum,
 datap1 type numc10,
 dataq1 type char32,
 datar1 type i,
 datas1 type sydatum,
 datat1 type numc10,
 datau1 type char32,
 datav1 type i,
 dataw1 type sydatum,
 datax1 type numc10,
 datay1 type char32,
 dataz1 type i,
end of local_long.
data:
ls_long type local_long,
lt_binary type standard table of local_long,
lt_sort_u type sorted table of local_long with unique key key1 key2,
lt_sort_n type sorted table of local_long with non-unique key key1 key2,
lt_hash_u type hashed table of local_long with unique key key1 key2,
lt_apsort type standard table of local_long.
field-symbols:
<ls_long> type local_long.
parameters:
min1 type i default 1,
max1 type i default 1000,
min2 type i default 1,
max2 type i default 1000,
i1 type i default 100,
i2 type i default 200,
i3 type i default 300,
i4 type i default 400,
i5 type i default 500,
i6 type i default 600,
i7 type i default 700,
i8 type i default 800,
i9 type i default 900,
fax type i default 1000.
types:
begin of measure,
 what(10) type c,
 size(6) type c,
 time type i,
 lines type i,
 reads type i,
 readb type i,
 fax_s type i,
 fax_b type i,
 fax(6) type c,
 iter type i,
end of measure.
data:
lt_time type standard table of measure,
lt_meantimes type standard table of measure,
ls_time type measure,
lv_method(7) type c,
lv_i1 type char10,
lv_i2 type char10,
lv_f type f,
lv_start type i,
lv_end type i,
lv_normal type i,
lv_size type i,
lv_order type i,
lo_rnd1 type ref to cl_abap_random_int,
lo_rnd2 type ref to cl_abap_random_int.
get run time field lv_start.
lo_rnd1 = cl_abap_random_int=>create( seed = lv_start min = min1 max = max1 ).
add 1 to lv_start.
lo_rnd2 = cl_abap_random_int=>create( seed = lv_start min = min2 max = max2 ).
ls_time-fax = fax.
do 5 times.
do 9 times.
 case sy-index.
 when 1. lv_size = i1.
 when 2. lv_size = i2.
 when 3. lv_size = i3.
 when 4. lv_size = i4.
 when 5. lv_size = i5.
 when 6. lv_size = i6.
 when 7. lv_size = i7.
 when 8. lv_size = i8.
 when 9. lv_size = i9.
 endcase.
 if lv_size > 0.
 ls_time-iter = 1.
 clear lt_apsort.
 ls_time-what = 'APSORT'.
 ls_time-size = lv_size.
 get run time field lv_start.
 do lv_size times.
 perform fill.
 append ls_long to lt_apsort.
 enddo.
 sort lt_apsort by key1 key2.
 get run time field lv_end.
 ls_time-time = lv_end - lv_start.
 ls_time-reads = 0.
 ls_time-readb = 0.
 ls_time-lines = lines( lt_apsort ).
 get run time field lv_start.
 do.
 add 1 to ls_time-readb.
 lv_i1 = lo_rnd1->get_next( ).
 lv_i2 = lo_rnd2->get_next( ).
 read table lt_apsort
 assigning <ls_long>
 with key key1 = lv_i1
 key2 = lv_i2
 binary search.
 if sy-subrc = 0.
 <ls_long>-data11 = sy-index.
 endif.
 get run time field lv_end.
 subtract lv_start from lv_end.
 if lv_end >= ls_time-time.
 exit.
 endif.
 enddo.
 get run time field lv_start.
 do.
 add 1 to ls_time-reads.
 lv_i1 = lo_rnd1->get_next( ).
 lv_i2 = lo_rnd2->get_next( ).
 read table lt_apsort
 assigning <ls_long>
 with key key2 = lv_i1
 key1 = lv_i2.
 if sy-subrc = 0.
 <ls_long>-data11 = sy-index.
 endif.
 get run time field lv_end.
 subtract lv_start from lv_end.
 if lv_end >= ls_time-time.
 exit.
 endif.
 enddo.
 get run time field lv_start.
 do fax times.
 lv_i1 = lo_rnd1->get_next( ).
 lv_i2 = lo_rnd2->get_next( ).
 read table lt_apsort
 assigning <ls_long>
 with key key1 = lv_i1
 key2 = lv_i2
 binary search.
 if sy-subrc = 0.
 <ls_long>-data21 = sy-index.
 endif.
 enddo.
 get run time field lv_end.
 ls_time-fax_b = lv_end - lv_start.
 get run time field lv_start.
 do fax times.
 lv_i1 = lo_rnd1->get_next( ).
 lv_i2 = lo_rnd2->get_next( ).
 read table lt_apsort
 assigning <ls_long>
 with key key2 = lv_i1
 key1 = lv_i2.
 if sy-subrc = 0.
 <ls_long>-data21 = sy-index.
 endif.
 enddo.
 get run time field lv_end.
 ls_time-fax_s = lv_end - lv_start.
 collect ls_time into lt_time.
 clear lt_binary.
 ls_time-what = 'BINARY'.
 ls_time-size = lv_size.
 get run time field lv_start.
 do lv_size times.
 perform fill.
 read table lt_binary
 transporting no fields
 with key key1 = ls_long-key1
 key2 = ls_long-key2
 binary search.
 if sy-index <> 0.
 insert ls_long into lt_binary index sy-tabix.
 endif.
 enddo.
 get run time field lv_end.
 ls_time-time = lv_end - lv_start.
 ls_time-reads = 0.
 ls_time-readb = 0.
 ls_time-lines = lines( lt_binary ).
 get run time field lv_start.
 do.
 add 1 to ls_time-readb.
 lv_i1 = lo_rnd1->get_next( ).
 lv_i2 = lo_rnd2->get_next( ).
 read table lt_binary
 assigning <ls_long>
 with key key1 = lv_i1
 key2 = lv_i2
 binary search.
 if sy-subrc = 0.
 <ls_long>-data11 = sy-index.
 endif.
 get run time field lv_end.
 subtract lv_start from lv_end.
 if lv_end >= ls_time-time.
 exit.
 endif.
 enddo.
 get run time field lv_start.
 do.
 add 1 to ls_time-reads.
 lv_i1 = lo_rnd1->get_next( ).
 lv_i2 = lo_rnd2->get_next( ).
 read table lt_binary
 assigning <ls_long>
 with key key2 = lv_i1
 key1 = lv_i2.
 if sy-subrc = 0.
 <ls_long>-data11 = sy-index.
 endif.
 get run time field lv_end.
 subtract lv_start from lv_end.
 if lv_end >= ls_time-time.
 exit.
 endif.
 enddo.
 get run time field lv_start.
 do fax times.
 lv_i1 = lo_rnd1->get_next( ).
 lv_i2 = lo_rnd2->get_next( ).
 read table lt_binary
 assigning <ls_long>
 with key key1 = lv_i1
 key2 = lv_i2
 binary search.
 if sy-subrc = 0.
 <ls_long>-data21 = sy-index.
 endif.
 enddo.
 get run time field lv_end.
 ls_time-fax_b = lv_end - lv_start.
 get run time field lv_start.
 do fax times.
 lv_i1 = lo_rnd1->get_next( ).
 lv_i2 = lo_rnd2->get_next( ).
 read table lt_binary
 assigning <ls_long>
 with key key2 = lv_i1
 key1 = lv_i2.
 if sy-subrc = 0.
 <ls_long>-data21 = sy-index.
 endif.
 enddo.
 get run time field lv_end.
 ls_time-fax_s = lv_end - lv_start.
 collect ls_time into lt_time.
 clear lt_sort_n.
 ls_time-what = 'SORT_N'.
 ls_time-size = lv_size.
 get run time field lv_start.
 do lv_size times.
 perform fill.
 insert ls_long into table lt_sort_n.
 enddo.
 get run time field lv_end.
 ls_time-time = lv_end - lv_start.
 ls_time-reads = 0.
 ls_time-readb = 0.
 ls_time-lines = lines( lt_sort_n ).
 get run time field lv_start.
 do.
 add 1 to ls_time-readb.
 lv_i1 = lo_rnd1->get_next( ).
 lv_i2 = lo_rnd2->get_next( ).
 read table lt_sort_n
 assigning <ls_long>
 with table key key1 = lv_i1
 key2 = lv_i2.
 if sy-subrc = 0.
 <ls_long>-data11 = sy-index.
 endif.
 get run time field lv_end.
 subtract lv_start from lv_end.
 if lv_end >= ls_time-time.
 exit.
 endif.
 enddo.
 get run time field lv_start.
 do.
 add 1 to ls_time-reads.
 lv_i1 = lo_rnd1->get_next( ).
 lv_i2 = lo_rnd2->get_next( ).
 read table lt_sort_n
 assigning <ls_long>
 with key key2 = lv_i1
 key1 = lv_i2.
 if sy-subrc = 0.
 <ls_long>-data11 = sy-index.
 endif.
 get run time field lv_end.
 subtract lv_start from lv_end.
 if lv_end >= ls_time-time.
 exit.
 endif.
 enddo.
 get run time field lv_start.
 do fax times.
 lv_i1 = lo_rnd1->get_next( ).
 lv_i2 = lo_rnd2->get_next( ).
 read table lt_sort_n
 assigning <ls_long>
 with table key key1 = lv_i1
 key2 = lv_i2.
 if sy-subrc = 0.
 <ls_long>-data21 = sy-index.
 endif.
 enddo.
 get run time field lv_end.
 ls_time-fax_b = lv_end - lv_start.
 get run time field lv_start.
 do fax times.
 lv_i1 = lo_rnd1->get_next( ).
 lv_i2 = lo_rnd2->get_next( ).
 read table lt_sort_n
 assigning <ls_long>
 with key key2 = lv_i1
 key1 = lv_i2.
 if sy-subrc = 0.
 <ls_long>-data21 = sy-index.
 endif.
 enddo.
 get run time field lv_end.
 ls_time-fax_s = lv_end - lv_start.
 collect ls_time into lt_time.
 clear lt_sort_u.
 ls_time-what = 'SORT_U'.
 ls_time-size = lv_size.
 get run time field lv_start.
 do lv_size times.
 perform fill.
 insert ls_long into table lt_sort_u.
 enddo.
 get run time field lv_end.
 ls_time-time = lv_end - lv_start.
 ls_time-reads = 0.
 ls_time-readb = 0.
 ls_time-lines = lines( lt_sort_u ).
 get run time field lv_start.
 do.
 add 1 to ls_time-readb.
 lv_i1 = lo_rnd1->get_next( ).
 lv_i2 = lo_rnd2->get_next( ).
 read table lt_sort_u
 assigning <ls_long>
 with table key key1 = lv_i1
 key2 = lv_i2.
 if sy-subrc = 0.
 <ls_long>-data11 = sy-index.
 endif.
 get run time field lv_end.
 subtract lv_start from lv_end.
 if lv_end >= ls_time-time.
 exit.
 endif.
 enddo.
 get run time field lv_start.
 do.
 add 1 to ls_time-reads.
 lv_i1 = lo_rnd1->get_next( ).
 lv_i2 = lo_rnd2->get_next( ).
 read table lt_sort_u
 assigning <ls_long>
 with key key2 = lv_i1
 key1 = lv_i2.
 if sy-subrc = 0.
 <ls_long>-data11 = sy-index.
 endif.
 get run time field lv_end.
 subtract lv_start from lv_end.
 if lv_end >= ls_time-time.
 exit.
 endif.
 enddo.
 get run time field lv_start.
 do fax times.
 lv_i1 = lo_rnd1->get_next( ).
 lv_i2 = lo_rnd2->get_next( ).
 read table lt_sort_u
 assigning <ls_long>
 with table key key1 = lv_i1
 key2 = lv_i2.
 if sy-subrc = 0.
 <ls_long>-data21 = sy-index.
 endif.
 enddo.
 get run time field lv_end.
 ls_time-fax_b = lv_end - lv_start.
 get run time field lv_start.
 do fax times.
 lv_i1 = lo_rnd1->get_next( ).
 lv_i2 = lo_rnd2->get_next( ).
 read table lt_sort_u
 assigning <ls_long>
 with key key2 = lv_i1
 key1 = lv_i2.
 if sy-subrc = 0.
 <ls_long>-data21 = sy-index.
 endif.
 enddo.
 get run time field lv_end.
 ls_time-fax_s = lv_end - lv_start.
 collect ls_time into lt_time.
 clear lt_hash_u.
 ls_time-what = 'HASH_U'.
 ls_time-size = lv_size.
 get run time field lv_start.
 do lv_size times.
 perform fill.
 insert ls_long into table lt_hash_u.
 enddo.
 get run time field lv_end.
 ls_time-time = lv_end - lv_start.
 ls_time-reads = 0.
 ls_time-readb = 0.
 ls_time-lines = lines( lt_hash_u ).
 get run time field lv_start.
 do.
 add 1 to ls_time-readb.
 lv_i1 = lo_rnd1->get_next( ).
 lv_i2 = lo_rnd2->get_next( ).
 read table lt_hash_u
 assigning <ls_long>
 with table key key1 = lv_i1
 key2 = lv_i2.
 if sy-subrc = 0.
 <ls_long>-data11 = sy-index.
 endif.
 get run time field lv_end.
 subtract lv_start from lv_end.
 if lv_end >= ls_time-time.
 exit.
 endif.
 enddo.
 get run time field lv_start.
 do.
 add 1 to ls_time-reads.
 lv_i1 = lo_rnd1->get_next( ).
 lv_i2 = lo_rnd2->get_next( ).
 read table lt_hash_u
 assigning <ls_long>
 with key key2 = lv_i1
 key1 = lv_i2.
 if sy-subrc = 0.
 <ls_long>-data11 = sy-index.
 endif.
 get run time field lv_end.
 subtract lv_start from lv_end.
 if lv_end >= ls_time-time.
 exit.
 endif.
 enddo.
 get run time field lv_start.
 do fax times.
 lv_i1 = lo_rnd1->get_next( ).
 lv_i2 = lo_rnd2->get_next( ).
 read table lt_hash_u
 assigning <ls_long>
 with table key key1 = lv_i1
 key2 = lv_i2.
 if sy-subrc = 0.
 <ls_long>-data21 = sy-index.
 endif.
 enddo.
 get run time field lv_end.
 ls_time-fax_b = lv_end - lv_start.
 get run time field lv_start.
 do fax times.
 lv_i1 = lo_rnd1->get_next( ).
 lv_i2 = lo_rnd2->get_next( ).
 read table lt_hash_u
 assigning <ls_long>
 with key key2 = lv_i1
 key1 = lv_i2.
 if sy-subrc = 0.
 <ls_long>-data21 = sy-index.
 endif.
 enddo.
 get run time field lv_end.
 ls_time-fax_s = lv_end - lv_start.
 collect ls_time into lt_time.
 endif.
enddo.
enddo.
sort lt_time by what size.
write: / ' type | size | time | tab-size | directread | std read | time direct | time std read'.
write: / sy-uline.
loop at lt_time into ls_time.
write: / ls_time-what, '|', ls_time-size, '|', ls_time-time, '|', ls_time-lines, '|', ls_time-readb, '|', ls_time-reads, '|', ls_time-fax_b, '|', ls_time-fax_s.
endloop.
form fill.
lv_i1 = lo_rnd1->get_next( ).
lv_i2 = lo_rnd2->get_next( ).
ls_long-key1 = lv_i1.
ls_long-key2 = lv_i2.
ls_long-data1 = lv_i1.
ls_long-data2 = lv_i2.
ls_long-data3 = lv_i1.
ls_long-data4 = sy-datum + lv_i1.
ls_long-data5 = lv_i1.
ls_long-data6 = lv_i1.
ls_long-data7 = lv_i1.
ls_long-data8 = sy-datum + lv_i1.
ls_long-data9 = lv_i1.
ls_long-dataa = lv_i1.
ls_long-datab = lv_i1.
ls_long-datac = sy-datum + lv_i1.
ls_long-datad = lv_i1.
ls_long-datae = lv_i1.
ls_long-dataf = lv_i1.
ls_long-datag = sy-datum + lv_i1.
ls_long-datah = lv_i1.
ls_long-datai = lv_i1.
ls_long-dataj = lv_i1.
ls_long-datak = sy-datum + lv_i1.
ls_long-datal = lv_i1.
ls_long-datam = lv_i1.
ls_long-datan = sy-datum + lv_i1.
ls_long-datao = lv_i1.
ls_long-datap = lv_i1.
ls_long-dataq = lv_i1.
ls_long-datar = sy-datum + lv_i1.
ls_long-datas = lv_i1.
ls_long-datat = lv_i1.
ls_long-datau = lv_i1.
ls_long-datav = sy-datum + lv_i1.
ls_long-dataw = lv_i1.
ls_long-datax = lv_i1.
ls_long-datay = lv_i1.
ls_long-dataz = sy-datum + lv_i1.
ls_long-data11 = lv_i1.
ls_long-data21 = lv_i1.
ls_long-data31 = lv_i1.
ls_long-data41 = sy-datum + lv_i1.
ls_long-data51 = lv_i1.
ls_long-data61 = lv_i1.
ls_long-data71 = lv_i1.
ls_long-data81 = sy-datum + lv_i1.
ls_long-data91 = lv_i1.
ls_long-dataa1 = lv_i1.
ls_long-datab1 = lv_i1.
ls_long-datac1 = sy-datum + lv_i1.
ls_long-datad1 = lv_i1.
ls_long-datae1 = lv_i1.
ls_long-dataf1 = lv_i1.
ls_long-datag1 = sy-datum + lv_i1.
ls_long-datah1 = lv_i1.
ls_long-datai1 = lv_i1.
ls_long-dataj1 = lv_i1.
ls_long-datak1 = sy-datum + lv_i1.
ls_long-datal1 = lv_i1.
ls_long-datam1 = lv_i1.
ls_long-datan1 = sy-datum + lv_i1.
ls_long-datao1 = lv_i1.
ls_long-datap1 = lv_i1.
ls_long-dataq1 = lv_i1.
ls_long-datar1 = sy-datum + lv_i1.
ls_long-datas1 = lv_i1.
ls_long-datat1 = lv_i1.
ls_long-datau1 = lv_i1.
ls_long-datav1 = sy-datum + lv_i1.
ls_long-dataw1 = lv_i1.
ls_long-datax1 = lv_i1.
ls_long-datay1 = lv_i1.
ls_long-dataz1 = sy-datum + lv_i1.
endform.".
Thanks & Regards,
YJR.

List, hash table

Is it possible to implement a List with a hash table?

The Java "collections" all use different methods of holding the data. Each is suited to different circumstances.
Vector and ArrayList keep the data in a plain vanilla array, but with the magic that they keep track of how much of the array is actually being used, and if you try to add another entry when the array is full, they make a new, bigger array, copy all the data from the old array to the new array, and then make the old array available for garbage collection. (The main difference between Vector and ArrayList is that Vector is synchronized, i.e. it will not become corrupted if multiple threads attempt to access it at the same time. ArrayList is not synchronized, which means that in the normal case where only one thread is accessing it, it is faster.)
In a LinkedList each entry has handles to the next entry in the list and the previous entry.
In a Hashtable the entries are stored in an array, but the index of the array entry is calculated using a formula based on the hash key. The hash formula is basically, divide the hashkey by the number of entries in the array and take the remainder. The hashkey itself depends on the object, but basically it is a formula that generates an integer out of something that can be considered teh "key value" of the object. It is possible -- indeed it happens all the time -- that two different objects will have the same hash key or that two objects with different hash keys will hash to the same index, so hashtable does some extra work to deal with such "collisions".
Each has its advantages. You can find an entry very quickly in a Hashtable: you find the hashkey, perform the hash function, go to that entry in the array, and kablam, you're there. The time to find an entry in the hashtable is independent of the number of entries in the table. Compare this to a Vector or LinkedList, where the only one to find a desired entry is to start at the beginning and search one by one until you find the one you want. The main drawback to a Hashtable is that the order you get out of the hash function is essentially random. You can read a Hashtable sequentially but the order has no particular significance.
A LinkedList is a good choice when order is important and there are a lot of inserts and/or deletes in the middle of the list. All that is necessary to add an entry is to change the handles on the entries that come before and after. While in your mind you might picture all the entries after being moved down to make room, physically none of them have to move, all that changes is handles. The main drawbacks to a LinkedList are: (a) there's some overhead involved in storing the handles and keeping them updated; and (b) it's not easy to jump to an arbitrary entry number, like if you want #12, you would have to loop through the first 11.
Vector and ArrayList are fast and simple when you are only or mostly adding or removing from the end of the list, and when you don't often need to search by key.

Hash table/Collection

Similar Messages

Maybe you are looking for