Variable Cell Range

Question

How do I use variables to define a cell range?
I have a series of data elements that are organized by date. I need to find a list of dates when specific events have occurred (each event is marked by a flag value of 1). I'm using VLOOKUP to find the first date when the event occurs. For the next date I need to adjust the cell range I'm searching so that it won't pick up the first occurence of the flag value (1).
Example:
1st query =VLOOKUP(1,G3..G223,51,0)
The first query returns a date that is in row 12. I now need to make the second query look for rows 13 through 223.
Overall I need to create over 500 such queries (50 columns of data and 10 events in each row), so typing in each query individually is not an appealing option.
Thanks!

Answer 1

Hi Dad,
I'm having some trouble with your description of the data table. If I read it correctly, the cells in column G contain either a 1 or are empty (or contain a zero). If this is correct, and you are using column G to hold the compare range, then, as the VLOOKUP description in AppleWorks Help states, "If the values in the compare range are not in strict ascending or descending order, or the compare range does not contain an inclusive range from the highest to lowest possible value, the results can be unpredictable." It's very difficult to place the values 0 and 1 into 221 individual cells in "strict ascending order."
VLOOKUP(v,cr,os,m) looks for a specific value (v) in a strictly ordered list of values (cr), and when that value is found*, returns the value in the cell that is in the same row and offset a specific number of columns (os) to the right.
*The method of comparison (m) determines whether an exact match is necessary or if the comparison can be <=v or >=v.
•From the Compare range in your formula, your table has 221 rows (3 through 223). My assumption is that you are recording data for 221 specific dates.
•From the offset value in the formula (51) the table has 52 columns—a compare range column, a result column, and 50 others between them.
•From your formula, it appears that only one column of the chart is being used as a compare range for a particular search (event?).
•You state you have 50 columns of data and that there are 10 events in each row (of 52? cells).
From the last statement, I infer that there are 50 distinct possible events (one for each column), and that 10 of these 50 events occur on each date. Is that correct?
If I understand the description, then my impression is that VLOOKUP is not an effective tool for this job.
Instead, I would suggest a larger table and a set of formulas which will construct a list of the dates on which each event occurs. (Note that the maximum length of a formula, and the maximum length of data for a single cell are both 255 characters. This may necessitate some adjustment to the formulas if one event occurs a great number of times.)
The larger table will consist of two (or three) sections:
•a data entry section much like my understanding of your current table. One column will contain a list of dates. Fifty other columns will each represent a single type of event. Each cell in that column will contain a 1 if the event occurred on the date listed in that row, or will be empty if the event did not occur on that date. for illustration purposes, the dates will be listed in F3..F223, and the events in columns G..BD, with the occurence of Event 1 reported in G3..G223.
•A calculated section which copies the contents of the data block, substituting the correct date for each occurrence of a 1 in the data. In this block (BF3..DC223), column BF will list the dates on which event 1 occurred, column DC the dates on which event 50 occurred. Row 2 (or Rows 1 and 2) in this secton will repeat the headers in the data entry section.
Formulas:
BF1: =G1
Fill this formula Down and Right to DC2
BF3: =IF(G3=1,=DATETOTEXT($F3),"")
Fill this formula Down and Right to DC223
Collecting the dates:
Open a new Word Processor document.
For EACH event, switch back to the spreadsheet document, select the full column containing the dates for that event (eg. BF1..BF223 for Event 1) and Copy.
Switch to the word processor document and Paste, then press shift-return twice (This enters a visual separation that will not be removed in the next step.)
Save the (temporary) WP document. You will have to name it the first time. After that, just press command-S. (This gives you a fall back if you make—and notice—an error along the way.
Repeat these three steps until you have transfered all 50 columns of data (including the empty cells in each column) into a single list in the WP document.
Now use Find/Change to remove all of the empty lines in the list.
Press command-F to open the Find/Change dialogue.
Type "\p\p" into Find and "\p" into Change (both without the quotes).
Repeat the next three steps until AppleWorks reports "0" occurences were changed.
Click Change All.
Click OK to acknowledge the warning that this action is irreversible.
Read the number of changes that occurred, then Click OK to close this alert.
You will now have a single column list of each event, followed by the dates on which it occurred. If you want to show this list as a table (in a spreadsheet), Select and copy each section Event and dates it occurred) individually, switch to the spreadsheet, click on the cell where you want that column of dates to begin, and Paste. Repeat.
It may be possible to automate this last part, either through a further section in the spreadsheet, or through the use of an AppleScript to collect and organize the calcualted data.
Regards,
Barry