Re: How do I pass $1 to s///?

[Happy-the-monk]

in reply to How do I pass $1 to s///?

backreferences in perlre are used to be written \1, \2 ... tweetiepooh informs me that my perldoc used was outdated... and ikegami again corrects that.

Update: your programme prints "This is fish".
What did you expect it to print? "This is fish 1"?

Further update: see ikegami's solution below.

Third and then fourth update - in italics

Cheers, Sören

[Anonymous Monk]

> your programme prints "This is fish".
...and gives a warning about $1 being uninitialised :(

> What did you expect it to print? "This is fish 1"?
Yeah. I've tried "fish \1", "fish \\1", "fish \\\1" as well though with no more luck!

[tweetiepooh]

\1,\2

If warnings are on using these lead to


\1 better written as $1


There is a section in perlre about it.

[ikegami]

Still not quite right.

Backreferences are \1, \2, etc in the LHS (regexp part) of the substitution.
Backreferences are $1, $2, etc in the RHS (substitituion part) of the substitution.

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