Question

I have a file with the following pattern
’21pro_ABCD_EDG_10800_48052_2 0.0′

How do i replace the _[0-9] with a ,(comma)
so that i can get the output as

21pro_ABCD_EDG,10800,48052,2, 0.0

Answer 1

To replace the _[0-9] with a , you can do this:

$s =~ s/_([0-9])/,$1/g 

#the same without capturing groups
$s =~ s/_(?=[0-9])/,/g;

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Edit:
To get the extra comma after the 2 you can do this:

#This puts a , before all whitespace.
$s =~ s/_(?=[0-9])|(?=\s)/,/g;

#This one puts a , between [0-9] and any whitespace
$s =~ s/_(?=[0-9])|(?<=[0-9])(?=\s)/,/g;