Modifying a large string

I have a For Loop that reads and modifies a 40 meg file. The file is a log of GPS and CAN messages. The Labview App will modify the data of one certain message type. This all works but it takes 4 and a half minutes to complete. Is there a faster way to do this other than creating a DLL? Is it due to Labview creating a new string every time the string's modified with the Replace Substring Function?
Thank You
Attachments:
Labview VIs.zip ‏42 KB

Ah, I see what you are trying to do now. You are taking the read distance, recomputing the distance, and replacing the same data in the file.
One of your biggest issues is that you are forking your wires a lot. And that is a potential data copy. And if you are copying large data, that takes a long time. Instead, you should be trying to do as much in series as possible. I changed your subVIs to use Scan From String and Format Into String instead of trying to increment value to read and convert to number multiple times. This also allows you to build up the string to replace and do a single replacement.
It might be worth trying Raven's suggestion of reading a single line at a time. You might also want to look into the Producer/Consumer architecture to put the writing to the new file in parallel with your processing of the file.
There are only two ways to tell somebody thanks: Kudos and Marked Solutions
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Attachments:
DistanceFix.zip ‏19 KB

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Need help on breaking a large string into substringsto fit in a line

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Good day all,
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I am upgrading from 6.0.2 to 6.1. Several large (2500 rows by 250 columns or larger) string arrays are used as inputs into subvi's. Under 6.0.2, these functions run in tenths of seconds, while under the converted 6.1 vi's they run in 20 seconds or more!
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Certified Professional Instructor
Certified LabVIEW Architect
LabVIEW Champion
"... after all, He's not a tame lion..."
Be thinking ahead and mark your dance card for NI Week 2015 now: TS 6139 - Object Oriented First Steps

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> string str - "practical example is always needed"
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Very Large String

I have a String that is suppose to hold info of about 200 MB, but when the string grows my program crashes giving a OutOfMemory Exception.
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Or will shifting to Java5.0 help solve this sort of problems.
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I have a one-gallon tank of water, which is less than
the five gallons I want to fill into it, but I don't expect it to overflowI very well understand what I am asking for.... I
expect my system (program) to become slow because I
guess we all know what Virtual memory stands for?Yes, very slow memory. o_O
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stop my application.It isn't.
You did not tell the JVM to allocate enough heap to hold objects that large.
You are free to configure your system with a large swap area
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Not sure if that will succeed though
(AFAIK the JVM requests a contiguous memory block for the heap - your success might depend on your OS).
Note, if you are building a large String, you should probably be using the StringBuffer class.
If your largest object is expected to be in the order of 200MB in size, you'll probably need a heap size in the order of half a gig.
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Large string into the VARCHAR2 field parsing problem

Guys,
SQL> select * from v$version;
BANNER
Oracle Database 10g Enterprise Edition Release 10.2.0.4.0 - 64bi
PL/SQL Release 10.2.0.4.0 - Production
CORE 10.2.0.4.0 Production
TNS for Solaris: Version 10.2.0.4.0 - Production
NLSRTL Version 10.2.0.4.0 - Production
My problem is: The frontend of the application sends a large string into the VARCHAR2 (4000 BYTES) field.
The string it sends is somewhat like the samples given below. I need to parse and put them in the tables
as shown below. Please let me know, if you have any questions. -
Crit: Some text1.
Proficient (points 2): Some more text1.
Comment1...........................................
..Comment1
Crit: Some text2.
Non-performance (points 0): Some more text2.
Crit: Some text3.
Distinguished (points 3): Some more text3.
Crit: Some text4.
Distinguished (points 3): Some more text4.
Table 1
Crit          points          comment        morecomment
Some text1.     2           Some more text1. Comment1.............................Comment1
Some text2.     0           Some more text2.
Some text3.     3           Some more text3.
Some text4.     3           Some more text4.
Table 2
Overall Comment
Crit: Some text1.
Proficient (points 2): Some more text1.
Crit: Some text2.
Non-performance (points 0): Some more text2.
Crit: Some text3.
Distinguished (points 3): Some more text3.
Crit: Some text4.
Distinguished (points 3): Some more text4.
Overall comments:
Blah2 Blah2 Blah2!
Some more blah2 blah2 blah2.
Table 1
Crit          points          comment        morecomment
Some text1.     2           Some more text1.
Some text2.     0           Some more text2.
Some text3.     3           Some more text3.
Some text4.     3           Some more text4.
Table 2
Overall Comment
Blah2 Blah2 Blah2!
Some more blah2 blah2 blah2.
Crit: Some text1.
Proficient (points 2): Some more text1.
Comment1...........................................
..Comment1.
Crit: Some text2.
Non-performance (points 0): Some more text2.
Comment2...............................Comment2.
Crit: Some text3.
Distinguished (points 3): Some more text3.
Crit: Some text4.
Distinguished (points 3): Some more text4.
Overall comments:
Blah1 Blah1 Blah1!Some more blah1 blah1 blah1.
Table 1
Crit          points          comment        morecomment
Some text1.     2           Some more text1. Comment1.............................Comment1
Some text2.     0           Some more text2. Comment2...............................Comment2.
Some text3.     3           Some more text3.
Some text4.     3           Some more text4.
Table 2
Overall Comment
Blah1 Blah1 Blah1!Some more blah1 blah1 blah1.--------------------------------------------------------------------
My code which doesn't work
WITH t AS
(SELECT 'Crit: Some text1.
Proficient (points 2): Some more text1.
Crit: Some text2.
Non-performance (points 0): Some more text2.
Crit: Some text3.
Distinguished (points 3): Some more text3.
Crit: Some text4.
Distinguished (points 3): Some more text4.
Overall comments:
Blah2 Blah2 Blah2!
Some more blah2 blah2 blah2.' string
FROM   dual)
SELECT SUBSTR(REGEXP_SUBSTR(string,'Crit: +$', 1, level), 12) "Crit",
       SUBSTR(REGEXP_SUBSTR(string,'points [^\)]+', 1, level), 8) "points",
       SUBSTR(REGEXP_SUBSTR(string,'\):^[[:alnum:]]+$', 1, level), 3) "comment",
       SUBSTR(REGEXP_SUBSTR(string,'^[[:alnum:]]+$', 1, level), 1) "morecomment"
FROM   t
CONNECT BY LEVEL <= (LENGTH(string) - LENGTH(REPLACE(string, 'Crit:')))/5
WITH t AS
(SELECT 'Crit: Some text1.
Proficient (points 2): Some more text1.
Comment1...........................................
..Comment1
Crit: Some text2.
Non-performance (points 0): Some more text2.
Crit: Some text3.
Distinguished (points 3): Some more text3.
Crit: Some text4.
Distinguished (points 3): Some more text4.' string
FROM   dual)
SELECT SUBSTR(string, INSTR(string, 'Overall comments:', -1) + 18) "overall_comment"
FROM   t
CONNECT BY LEVEL <= (LENGTH(string) - LENGTH(REPLACE(string, 'Crit:')))/5Edited by: abyss on Sep 17, 2010 12:26 PM

Hi,
Except for the morecomment column, you almost had it.
Oracle documentation often refers to ^ and $ as meaning beginnig- and end-of-line, but they seem to mean beginning- and end-of-string.
Aside from that , I just changed a few details (like ' +' to '.+').
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                                      , LEVEL + 1
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                          , LENGTH ( REGEXP_SUBSTR ( string
                                                            , 'Crit:.*'
                                           , 1
                                           , LEVEL
                                  ) +
                          LENGTH ( REGEXP_SUBSTR ( string
                                            , 1
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FROM   t
CONNECT BY LEVEL <= (LENGTH(string) - LENGTH(REPLACE(string, 'Crit:')))/5
; This gets the results you requested from the data you posted. I don't know if it gets those results for the right reasons or not, since you didn't post any reasons for why you want those results. Always explain why you want the results you do, giving specific examples from the sample data.
The morecomment (called more_cmnt above) is much more complicated, since it involves scanning across multiple lines. I wouldn't be surprised if there is a simpler way than what I posted above.
I do not recommend doing this in pure SQL. I suggest a PL/SQL function, because debugging and maintenance would be so much easier.
To populate table2:
WITH     got_pos         AS
     SELECT     string
     ,     INSTR (string, 'Overall comments:', -1)     AS pos
     FROM     t
SELECT SUBSTR ( string
            , pos + 18
            )     AS overall_comment
FROM    got_pos
WHERE     pos     > 0
;

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/ Elvez

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Note : Please mark the helpful answers

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because attribute will lost during redirect to another domain.
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Rgds
Padmanava

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You must use Java to do this, the Execute Script operation makes it simple. I have put together a little process to demonstrate, and I can paste the Java from the Execute Script step below.
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Let me know if I'm not clear enough with my explanation.
Jeff A Yates
http://www.avoka.com
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import java.sql.PreparedStatement;
import java.sql.Statement;
import java.sql.ResultSet;
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Hi Steve,
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Thanks for the feedback,
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Steve Alexander wrote:
In case anyone is interested, I solved my problem. I was mis-diagnosing the problem
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"Steve Alexander" <[email protected]> wrote:
Thanks Bruce,
FYI - I have reproduced the problem on WL7.0. I have turned it in to support
as you
suggested.
Steve
Bruce Stephens <[email protected]> wrote:
Hi Steve,
This does not ring any bells, however I would suggest that you file a support
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is an option you might try a later release (7.0).
Bruce
Steve Alexander wrote:
Hi,
I currently have an EJB that returns a String[] array that I have implementedas
a Web Service. When I execute a Java client (JSP) from Weblogic, I don'thave a problem
as long as the returned array is relatively small, but when the arraystarts to get
a little larger (say 20 elements, about 30 chars each), I consistentlyget:
SAXException: java.lang.IllegalArgumentException:array element type mismatch.
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(using the MS SOAP Toolkit), it works fine. I have returned as many as15000 - 20000
array elements in one call. And since I am calling the same Weblogic
EJB
with the
MS client, I know it's a problem with the Java client, not the EJB.
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Hi All,
2 Quick Questions
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QUESTION 2:
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Answer 2:
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http://jakarta.apache.org/
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http://www-igm.univ-mlv.fr/~lecroq/string/tunedbm.html
Regards, and have fun,
-Troy

Format large string for mysql

I am reading a large txt file that contains sigle quotes and double quotes... I want to format the string and send it to a blob cell in mysql. I need to add an escaoe character before single quotes and double quotes. Any suggestions?

john joe wrote:
I am reading a large txt file that contains sigle quotes and double quotes... I want to format the string and send it to a blob cell in mysql. I need to add an escaoe character before single quotes and double quotes. Any suggestions?
Yes! Use "Search and Replace String" with "replace all?" = True. Replace "'" with "\'" and replace """ with "\"".
Cheers.
Message Edited by tbd on 02-12-2007 11:06 PM
"Inside every large program is a small program struggling to get out." (attributed to Tony Hoare)

Cipher - encrypt large String variable

Hello,
I have a jUnit test for a simple Cipher encryption/decryption.
I want to write a test to encrypt large data.
Do I have to change the encryption variable type from String to a Stream class?
Anyone have suggestion?
package no.ssb.cipher;
import org.junit.*;
import static org.junit.Assert.*;
* Unit test for simple App.
public class SimpleStringCipherTest {
private SimpleStringCipher simpleStringCipher;
* Create the test case
* @param testName name of the test case
@Before
public void setUp()
simpleStringCipher = new SimpleStringCipher("tvnw63ufg9gh5392");
@Test
public void testBasicEncyption() throws Exception {
String plainText = "2010 starts new decade.";
String encrypted = simpleStringCipher.encrypt(plainText);
System.out.println("Encrypted: " + encrypted);
assertTrue(!plainText.equals(encrypted));
String decrypted = simpleStringCipher.decrypt(encrypted);
assertEquals(plainText, decrypted);
@Test
public void testEncryptionIsNotURLSafe() throws Exception{
String plainText = "2010 starts new decade.";
String expectedValue = "abe6vPUFQ4xSMezuFF2HBNC3dW98iifMeM027PKKnNw=";
String encrypted = simpleStringCipher.encrypt(plainText);
assertTrue(!plainText.equals(encrypted));
assertTrue(expectedValue.equals(encrypted));
String decrypted = simpleStringCipher.decrypt(encrypted);
assertEquals(plainText, decrypted);
@Test(expected=IllegalArgumentException.class)
public void testInvalidSecretKey() throws Exception{
SimpleStringCipher invalidCipher = new SimpleStringCipher("tull");
@Test(expected=Exception.class)
public void testDecryptInvalidEncryptedString() throws Exception {
simpleStringCipher.decrypt("abe6vPUFQ4xSMezuFF2HBNC3dW98jjfMeM027PKKnNw");
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Sorry, I am beginner and new in Cipher.
Hope my following question make more sense.
In production we have an error when decrypting
large data.
My existing unit test is shown and class I am testing
How can I write a new test, simulating the production error we have?
1.@Test
2.public void testBasicEncyption() throws Exception {
3.String plainText = "text to be encrypted."
4.String encrypted = simpleStringCipher.encrypt(plainText);
5.System.out.println("Encrypted: " + encrypted);
6.assertTrue(!plainText.equals(encrypted));
7.String decrypted = simpleStringCipher.decrypt(encrypted);
8.assertEquals(plainText, decrypted);
* Class to test *
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import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
import org.apache.commons.codec.binary.Base64;
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// linebreak
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if(secretKey.length()!=16){
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key = new SecretKeySpec(secretKey.getBytes(), "AES");
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coder = new Base64(32, linebreak, false);
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t.printStackTrace();
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byte[] encypted = coder.decode(codedText.getBytes());
cipher.init(Cipher.DECRYPT_MODE, key);
byte[] decrypted = cipher.doFinal(encypted);
return new String(decrypted);
Edited by: 999969 on Apr 14, 2013 10:38 PM

Modifying a large string

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