How to use Regular Expression In Find and Replacement - regex

Question

I've one CSV file which has almost 50k records. I want to remove the unnecessary records from this file. Can anyone tell me how can I achieve this by Regex through Find and Replacement?
The data looks like this:
Item Code,,Qty
CMAC-389109,,6
,Serial No.,
,954zg5,
,ffnaw8,
,gh8731,
,gxj419,
,hc6y9q,
,y65vh8,
CMAC-394140,,1
,Serial No.,
,4cu3z7,
and I want to convert this data to below format:
ItemCode,Serial Number,Qty
CMAC-389109,"954zg5, ffnaw8, gh8731, gxj419, hc6y9q, y65vh8",6
CMBM-394140,"4cu3z7",1

Answer 1

Here's a regex which captures two groups (Item Code and Shelf):
^([^,]*?)(?:,(?:[^,]+)?){5},([^,]+),.*$
I don't know what syntax DW uses to reference groups. But usually it's either $n or \n, so in your case, you can put $1, $2 in the "replacement" field of the search/replace box. Or \1, \2.
If you have access to a Linux environment (OS-X and Cygwin should work too), you can use the command-line tools cut and grep to accomplish this quite easily:
cat <filename> | cut -d ',' -f 1,7 | grep -v "^,$" > <output_file>
The parameters I used on cut are:
-d
Delimiter (by which character the fields are separated)
-f
Fields (which fields to include in the output).
... and grep:
-v
Invert pattern: Only include lines in output not matching the regex.
Given your data in your question, the above command will yield this result:
Item Code,Shelf
CMAC-386607,M5-2
CMAC-389109, F2-3
This should also be quite efficient, as cut works on a stream, and only loads as much data into memory as necessary. So you don't need to load the whole file before executing the task. It being a large file, this might be handy.