Regex Replace starting from an n occurence

[Nouha]

Hello everyone, 

if someone can help figure this problem i'd be greatful

my data looks like this 

field	starting after	nbcar
,A,BC,AZRG	1	1
,DB,CQ,AEYG	2	1
,ETR,AC,A3,4AQW	2	2

and what i want to do is remove from "Field" the specified number of commas in "nbcar" after the comma specifed in the "starting after"

so it would look like this 

field	starting after	nbcar	new_Field
,A,BC,AZRG	1	1	,ABC,AZRG
,DB,CQ,AEYG	2	1	,DB,CQAEYG
,ETR,AC,A3,4A,QW,TRZ	2	2	,ETR,ACA34A,QW,TRZ

I thought maybe it can be done with Regex_replace but i can't seem to make it work

Thank you all, 

Nouha

[CharlieS]

There's probably a more succinct way to do this with RegEx, but here's a solution without RegEx. I split each field into rows and used the [starting after] and [nbcar] fields to determine how to concatenate the rows back together (with or without commas). A Tile tool provided a grouped record ID field. 

[WillBowman]

((,[^,]*){2}),(.*)
 
Basically replace 2 with the amount of commas before the one you want to replace and then concatenate groups 1 and 3. In alteryx use the regex parse tool and I think you can concatenate there.
 
In python or R just +
 
Here's the output i got:
 
Full match 0-20 `,ETR,AC,A3,4A,QW,TRZ`
Group 1. 0-7 `,ETR,AC`
Group 2. 4-7 `,AC`
Group 3. 8-20 `A3,4A,QW,TRZ`
 
 

To account for the NBCHAR you need to capture subsequent groups and then run a separate replace (in scripting we could just use replace but this is alreryx). For this you want

((,[^,]*){2})((,[^,]*){2})(.*)

And to run replace “,” on group 3. Then concat groups 1,3,5

[ponraj · Accepted solution]

Here is the sample workflow for your case.  Hope this is helpful. workflow

InputResults