Regex Question : Substitution

azatoth has asked for the wisdom of the Perl Monks concerning the following question:

Hi Guys -

I have looked in Supersearch, but can't find anything close to my query...although, i couldn't really think of any good search strings either :P

#!/usr/bin/perl -w

use strict;

# variables

my $eng;


# main 

print "String : \n";
($eng = <STDIN>);

($eng =~ s/u/a/i) if ($eng =~ /^.*u.*/g);

print $eng;
[download]

The code above does the following. If I enter
"Jump up, Helmut!",
the result is
"Jamp up, Helmut!".
What I want though, is
"Jamp ap, Helmat!".
I.E Substitute every 'u' for an 'a', instead of just the first one.

Any ideas?

Thanks

Azatoth a.k.a Captain Whiplash

Get YOUR PerlMonks Stagename here!

Comment on Regex Question : Substitution Download Code

Replies are listed 'Best First'.
Re: Regex Question : Substitution by BooK (Curate) on Feb 02, 2001 at 15:56 UTC
Or even shorter, use the transliteration operator: `$eng =~tr/u/a/;` Documentation to be found at: tr and perlop	[reply] [d/l]
Re: Re: Regex Question : Substitution by $code or die (Deacon) on Feb 02, 2001 at 17:14 UTC
For the question he'll need to use `$eng =~tr/uU/aA/;` $code or die Using perl at The Spiders Web	[reply]
Re: Re: Re: Regex Question : Substitution by japhy (Canon) on Feb 02, 2001 at 22:42 UTC
No, he only wants `tr/uU/a/` (which is the same as `tr/uU/aa/`. `japhy` -- Perl and Regex Hacker	[reply]
Re: Re: Regex Question : Substitution by petral (Curate) on Feb 03, 2001 at 07:26 UTC
Er, I think he wants t/Uu/Aa/ p oopsdate: Never mind. (I gotta keep this set at a larger font.)	[reply]
Re: Regex Question : Substitution by mirod (Canon) on Feb 02, 2001 at 15:54 UTC
Just replace `$eng =~ s/u/a/i) if ($eng =~ /^.u./g);` by `$eng =~ s/u/a/ig;` There is no need to test whether the substitution will work, just do it. I think you wanted to write initially was more: `$eng =~ s/u/a/i while ($eng =~ /^.u./g);` but even if this works it is really inneficient. To start with the `/^.u./` is strictly equivalent to /u/ except that it is slower (you should read Death to Dot Star! for more on the evils of .*)	[reply] [d/l] [select]
Re: Regex Question : Substitution by ChOas (Curate) on Feb 02, 2001 at 15:53 UTC
Hi! use a 'g' in you substitution, like you do in your search... And if your searching every sting with a regex to see if you want to replace it, better just take the chance of replacing it Anyways... it won't hurt if there are no 'u's there... `$eng =~ s/u/a/i => $eng =~ s/u/a/gio` GreetZ!, ChOas print "profeth still\n" if /bird\|devil/;	[reply] [d/l]
Re: Regex Question : Substitution by Beatnik (Parson) on Feb 02, 2001 at 18:27 UTC
The funny part is, you're using g in m// while you only need to check once, and you're not using g in s/// when you want all occurances swapped. Greetz Beatnik ... Quidquid perl dictum sit, altum viditur.	[reply]
Re: Regex Question : Substitution by dsb (Chaplain) on Feb 02, 2001 at 20:23 UTC
Try: `$eng =~ s/u/a/gi;` [download] Using the 'g' and 'i' modifiers to: 1. Substitute every instance of 'u' 2. Ignore case - kel -	[reply] [d/l]