Re: Search patern within pattern in a single substitute command

Here's one way:

#! perl -sw
use strict;

s[(?:\S+ ){2}\K((.).(..))][$2Y$3 $1], print while <DATA>;

=output

C:\test>junk56
col1 col2 cYl3 col3 col4 col5
1234 5678 9Y12 9012 3456 7890

=cut

__DATA__
col1 col2 col3 col4 col5
1234 5678 9012 3456 7890
[download]

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.

"Science is about questioning the status quo. Questioning authority".

In the absence of evidence, opinion is indistinguishable from prejudice.

Comment on Re: Search patern within pattern in a single substitute command Download Code

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Re^2: Search pattern within pattern in a single substitute command by toolic (Bishop) on Mar 04, 2011 at 01:37 UTC
Very cool. Your output doesn't quite match the OP's, but with this slight adjustment, we do: `use warnings; use strict; s[.{5}\K((.).(..))][$1 $2Y$3], print while <DATA>; __DATA__ col1 col2 col3 col4 col5 1234 5678 9012 3456 7890` [download] prints: `col1 col2 cYl2 col3 col4 col5 1234 5678 5Y78 9012 3456 7890` [download]	[reply] [d/l] [select]
Re^2: Search patern within pattern in a single substitute command by shobhit (Sexton) on Mar 04, 2011 at 04:57 UTC
Looking back now, I knew nested pattern `((.).(..))` and should have thought about it here. It turned out to be the key. What does the \K mean? If I don't include it I get o/p `col2 cYl2 col3 col4 col5 5678 5Y78 9012 3456 7890` [download] W/o `\K` the following works too, but I would like to understand \K `s[(.{5})((.).(..))(.*)][$1$2 $3Y$4$5], print while <DATA>;` [download] This is something I would have written if I had thought about the nested pattern in the first place....	[reply] [d/l] [select]
Re^3: Search patern within pattern in a single substitute command by BrowserUk (Patriarch) on Mar 04, 2011 at 05:24 UTC
What does the \K mean? from Perldoc perlre: "Character Classes and other Special Escapes" `\K Keep the stuff left of the \K, don't include it in $&` [download] It says that the bit of the regex preceding it is only used to locate the part of the string to be replaced, but isn't a part of the substitution. It just saves the need for an extra capture. Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". In the absence of evidence, opinion is indistinguishable from prejudice.	[reply] [d/l]
Re^4: Search patern within pattern in a single substitute command by shobhit (Sexton) on Mar 04, 2011 at 05:40 UTC
Makes sense. Thanks a lot for your help.	[reply]