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Re: One liner to subtract by 2

by choroba (Archbishop)
on Jul 24, 2013 at 14:05 UTC ( #1046122=note: print w/replies, xml ) Need Help??


in reply to One liner to subtract by 2

You can use the /e switch of the substitution operator: 
perl -pe 's/([0-9]{10})$/sprintf "%010d",$1-2/e'

[download]

Update: I am not sure how to search for the line, though, because you did not give any information on how these lines are structured. Adding that to the one-liner is easy, e.g. let's pretend we want to process lines beginning with 0TONY: 

perl -pe 's/([0-9]{10})$/sprintf "%010d",$1-2/e if /^0TONY/'

[download]

Update 2: sprintf added. Thanks derby.

لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ

Replies are listed 'Best First'.
Re^2: One liner to subtract by 2
by derby (Abbot) on Jul 24, 2013 at 14:08 UTC

    You'll lose leading zeros with that.

    -derby

    update: so perl -pe 's/([0-9]{10})$/sprintf("%010d", $1-2)/e'

[reply]
[d/l]
      Thanks, fixed.
      لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ
[reply]

        Thanks Guys

        the header is on the first line of my file so I'm doing the following

        perl -pe 's/(0-9{10})$/sprintf("%010d", $1-2)/e if $. ==1' TONYFILE.DAT

        for some reason it's not changing the count...it's still 496

        any idea what i'm missing here?

[reply]

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