From: GOTO Kentaro <gotoken@...>
Date: 2002-09-24T03:23:31+09:00
Subject: Re: another easy one...

At Tue, 24 Sep 2002 01:09:45 +0900,
Mark Probert wrote:
> My brain just isn't working this morn...

Ask ri :)

> Say, ch is a character and I want to find if it
> exists in a regexp /A-Za-z0-9_/.  How do I do it?
> 
>          irb> c.include?(/A-Za-z0-9_/)
>          "TypeError: cannot convert Regexp into String"

% ri 'String#include?'
-------------------------------------------------------- String#include?
     str.include? aString -> true or false
     str.include? aFixnum -> true or false
------------------------------------------------------------------------
     Returns true if str contains the given string or character.
        "hello".include? "lo"   #=> true
        "hello".include? "ol"   #=> false
        "hello".include? ?h     #=> true

% 

> I can do:
> 
>          irb> c.count("A-Za-z0-9_")
>          1
> 
> And look for a 0 being a non-match.

% ri String#count
----------------------------------------------------------- String#count
     str.count( [aString]+> ) -> aFixnum
------------------------------------------------------------------------
     Each aString parameter defines a set of characters to count. The
     intersection of these sets defines the characters to count in str.
     Any aString that starts with a caret (^) is negated. The sequence
     c1--c2 means all characters between c1 and c2.
        a = "hello world"
        a.count "lo"            #=> 5
        a.count "lo", "o"       #=> 2
        a.count "hello", "^l"   #=> 4
        a.count "ej-m"          #=> 4

%