From: "David A. Black" <dblack@...>
Date: 2008-04-26T23:53:10+09:00
Subject: Re: All occurances of a  character in a string

Hi --

On Sat, 26 Apr 2008, Raghu Go wrote:

> Hi - I am trying to figure out the ruby way of printing all occurances
> of a character in a string..
>
> The index method on string gives only the first occurance only.
>
> Example input string - abbccdaab
> desired output - 'a' = 0 6 7
>                 'b' = 1 2 8
>                 'c' = 3 4
>                 'd' = 5
>
> Any help greatly appreciated..

I have this really strong feeling that there's a really easy way, but
I can't think of it or find it. Meanwhile, if you're using 1.9 you
could do something like:

   str = "abcdbcdae"

   h = Hash.new {|h,k| h[k] = [] }
   str.each_char.map.with_index {|char, i| h[char] << i }

which would put a hash of results in h.

I just have this hunch that there was a way to accumulate offsets from
a scan or gsub operation, but I can't come up with it.


David

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