Repacing a string at a specific location with another in Vi (gVim)

ziggy25 · 03-18-2010, 02:01 PM

If i have a comma separated string like this one

Code:

aa,bb,cc,dd,ee
11,22,dd,3f,22

How can i replace the value on the 4th column with a specific value. For example if i want all values in the 4th column to be '55' the output would be

Code:

aa,bb,cc,55,ee
11,22,dd,55,22

Is this possible in VI or more specifically gVim on windows?

Thnks

Tinkster · 03-18-2010, 02:18 PM

vim

Code:

%s/\([^,][^,]*,[^,][^,]*,[^,][^,]*,\)[^,][^,]*\(,[^,][^,]*\)/\155\2/

penguiniator · 03-18-2010, 02:54 PM

In general, what you need are regular expressions. You would benefit from finding a good tutorial and learning them, and then reading about how Vim uses them: :help usr_27.txt and :help regular-expression.

ziggy25 · 03-18-2010, 04:20 PM

Quote:

Originally Posted by Tinkster

vim

Code:

%s/\([^,][^,]*,[^,][^,]*,[^,][^,]*,\)[^,][^,]*\(,[^,][^,]*\)/\155\2/

Hi Tinkster,

Could you explain what exactly is happening here.. Wouldnt this work only if the content is fixed length?

Thanks

ziggy25 · 03-18-2010, 04:22 PM

Quote:

Originally Posted by penguiniator

In general, what you need are regular expressions. You would benefit from finding a good tutorial and learning them, and then reading about how Vim uses them: :help usr_27.txt and :help regular-expression.

Thanks. I do try to learn them but the problem is i rarely use them so i just forget about them every time i learn them and have to refresh my memory. I do know the basics but not something as tough as this though

Tinkster · 03-18-2010, 04:37 PM

Quote:

Originally Posted by ziggy25

Hi Tinkster,

Could you explain what exactly is happening here.. Wouldnt this work only if the content is fixed length?

Thanks

What do you mean by "fixed length"? Only if there's 5 columns? Yes.
But that's easily fixed.

Atm we're looking for (and remembering):
Any number of anything not a comma followed by a comma (3x)(remember)
followed by anything not a comma
followed by a command and anything not a comma (remember)
and replace with
remembered1 55 remembered2

If the number of columns after the fourth were vaiable:

Code:

%s/\([^,][^,]*,[^,][^,]*,[^,][^,]*,\)[^,][^,]*\(,.*\)/\155\2/

Cheers,
Tink

chrism01 · 03-18-2010, 06:44 PM

One of the tricks with regexen is, when you've got one that works, save the instructions/example in a file for future ref. After a while you build up a collection which you can often amend to use on your next problem.
Once you got a bunch in one file, with an example usage of each, you'll start to see how they work.