From: Robert Klemme <shortcutter@...>
Date: 2011-03-12T00:58:46+09:00
Subject: Re: substitution in a regular expression

On Fri, Mar 11, 2011 at 2:39 PM, Mario Ruiz <tcblues@gmail.com> wrote:
> I want to replace the text for fecha on the string but I don't know how
> to do it:
>
>
> a=" id:'name',
>  label :'Name',
>  type:'string',
> idx : 3,
> fecha: 24/13/2009,
> whitelabel:'true',
> fecha: 11/01/2009"
>
>
> the regular expression I'm using is:
> /'?fecha'? *: *'(.*)' *, *$/
>
> and the result I want is:
> a=" id:'name',
>  label :'Name',
>  type:'string',
> idx : 3,
> fecha: 01/03/2010,
> whitelabel:'true',
> fecha: 01/03/2010"

Two ways:

irb(main):004:0> a=" id:'name',
irb(main):005:0"  label :'Name',
irb(main):006:0"  type:'string',
irb(main):007:0" idx : 3,
irb(main):008:0" fecha: 24/13/2009,
irb(main):009:0" whitelabel:'true',
irb(main):010:0" fecha: 11/01/2009"
=> " id:'name',\n label :'Name',\n type:'string',\nidx : 3,\nfecha:
24/13/2009,\nwhitelabel:'true',\nfecha: 11/01/2009"

irb(main):011:0> a[/^fecha:\s*(\S+)/, 1] = "REPLACED"
=> "REPLACED"
irb(main):012:0> a
=> " id:'name',\n label :'Name',\n type:'string',\nidx : 3,\nfecha:
REPLACED\nwhitelabel:'true',\nfecha: 11/01/2009"

irb(main):013:0> a.gsub(/^(fecha:\s*)\S+/) {$1+"ANOTHER_REPLACED"}
=> " id:'name',\n label :'Name',\n type:'string',\nidx : 3,\nfecha:
ANOTHER_REPLACED\nwhitelabel:'true',\nfecha: ANOTHER_REPLACED"

Note, that the first approach only replaces one occurrence.

Cheers

robert

-- 
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/