How to replace the value at specific position in var

Hi guys, I have a small newbie question. I have a variable = "a,b,c,a,d,f" and I have to replace the value at position 4 (comma as a separator, in this case it is "a") to something else. How to make it?

I'm pretty sure this was discussed, but I can't find it...

Thanks in advance!

Something like this maybe?

It can probably be done easier with regular expressions, but I don't know them that well (or in fact at all )

Something like this maybe?

It can probably be done easier with regular expressions, but I don't know them that well (or in fact at all )

I was thinking about something like this, and it's really can be made by looping in the new avr etc. But like you mentioned, there have to be a more rational way to made it by Regex. But but I don't know them too.

Ok, I read a few beginners tutorials on regular expressions and apparently you can parse comma-separated strings with a simple pattern like this:

(?<=\r|\n|^)(?!\r|\n|$)(?:(?:"(?<Value>(?:[^"]|"")*)"|(?<Value>(?!")[^,\r\n]+)|"(?<OpenValue>(?:[^"]|"")*)(?=\r|\n|$)|(?<Value>))(?:,|(?=\r|\n|$)))+?(?:(?<=,)(?<Value>))?(?:\r\n|\r|\n|$)[/code:2st6x3tn]
Easy-peasy!

Easy-peasy! <img src="{SMILIES_PATH}/icon_e_smile.gif" alt=":)" title="Smile">

oh man <img src="{SMILIES_PATH}/icon_e_surprised.gif" alt=":o" title="Surprised"> ... maybe you can give me simple example on https://regex101.com/ or something like that?

I really thank you.

That was a joke

I did some googling and turned out that parsing comma-separated strings with regex is quite a difficult task. So I copy-pasted that pattern from stackoverflow

That was a joke

Ok, now I think there is no way to perform it without using some cyclic operation... So the "tokenat & looping" method may be a decent decision or I will use array instead of var. Anyway thanx