From: Mike Stok <mike@...>
Date: 2001-01-31T06:01:50+09:00
Subject: [ruby-talk:10139] Re: Easy regex question

On Wed, 31 Jan 2001, Neil Conway wrote:

> Hi all,
>
> I just learned Ruby recently (coming from Perl/Java/Python), and I've got
> a simple question about regular expressions that I just can't seem to
> work out. I'm trying to SQL quote a string (for now, just replacing all
> single-quotes with backslash-single-quote - i.e. ' -> \').
>
> In Perl, the following works fine:
>
> $ perl
> $str = "it's me";
> $str =~ s/'/\\'/g;
> print "$str\n";
> it\'s me

[...]

> Can someone tell me:
>
> 2) The correct regex to do what I'm looking for

str.gsub(/'/, "\\\\'") or str.gsub(/'/) {"\\'"} seem to work:

irb(main):008:0> puts str.gsub(/'/, "\\\\'")
it\'s me
nil
irb(main):009:0> puts str.gsub(/'/) {"\\'"}
it\'s me
nil

This is because the \\\\ gets turned into \\ as the program gets read in,
and the \\ gets turned into \ by the regex engine.

If you can find Programming Ruby in a book store then page 64 has a
description of this.

Hope this helps,

Mike

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