Re^2: using s/ to not only substitute but also modify text

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Re^3: using s/ to not only substitute but also modify text by ikegami (Patriarch) on Nov 22, 2008 at 08:12 UTC
`s/.../.../;` [download] means `$_ =~ s/.../.../;` [download] The warning is issued when `$_` contains `undef`.	[reply] [d/l] [select]
Re^4: using s/ to not only substitute but also modify text by Anonymous Monk on Nov 23, 2008 at 01:14 UTC
Thanks ikegami. But I still don't understand why I get the error from a script containing the same logic of another, the only difference is that variable being the defaulted $_ while the other is user-defined Eg: my $r Below are the scripts I tested... I'd like to assign a string or even a large body of text to a variable other than $_ Can you help? Thanks. `my $r = "Time to work"; s/work/play/; print $r; #end of script 1 #script 2 $_ = "Time to work"; s/work/play/; print $_` [download]	[reply] [d/l]
Re^5: using s/ to not only substitute but also modify text by ikegami (Patriarch) on Nov 23, 2008 at 01:35 UTC
the only difference is that variable being the defaulted $_ while the other is user-defined Nope, no "user-defined" variables being used by `s///` in either snippet. `my $r = "Time to work"; s/work/play/; print $r;` [download] means `my $r = "Time to work"; $_ =~ s/work/play/; print $r;` [download] Since you never assigned anything to `$_`, you get a warning. Conversely, you never told `s///` to work on `$r`. Doing either will solve the problem. `my $_ = "Time to work"; s/work/play/; print $_;` [download] `my $r = "Time to work"; $r =~ s/work/play/; print $r;` [download]	[reply] [d/l] [select]
Re^6: using s/ to not only substitute but also modify text by Anonymous Monk on Nov 23, 2008 at 03:55 UTC