From: Steve Callaway <sjc2000_uk@...>
Date: 2005-05-18T21:53:07+09:00
Subject: Re: Variable substitution in a regex

Yeah, straightforward enough, moreover you can process
an array of vars as in the snippet I put up on
Rubyforge:

# function to regexp vars
def is_element_in_string?(in_string, in_array)
in_array.each do |line|
rx_test = /#{line}/
            if  in_string =~ rx_test
                             return true
            end
end
return false
end

# as an example we may wish to see whether a list of
football match results
# contains a result of a team we are interested in
varray = Array.new
# now populate the array with reegxps you wish to
match...
varray = ["Plymouth Argyle", "Blackburn Rovers" ,
"Manchester .*", "Tott.*"]

#Examples:
results = "Plymouth Argyle 5 - Cardiff 0"
puts is_element_in_string?(results, varray)
#=> true

results = "Watford 3 - Sunderland 0"
puts is_element_in_string?(results, varray)
#=> false, no match


results = "Man City 2 - Man Utd 0"
puts is_element_in_string?(results, varray)
#=> false
# since it obviously won't regexp unless we add "Man
U.*" to our array...
# e.g.
varray.push("Man U.*")
puts is_element_in_string?(results, varray)
# => true


--- Scott Pack <softwarespack@yahoo.com> wrote:
> Hi,
> 
> I am new to Ruby. Can I substitute the value of a
> variable into a regular expression? For example:
> 
> exp = /(\d+)/ #works
> exp = /(\d+)/ + 'some string value' #Not!
> 
> Thanks,
> 
> S
> 
> 
> 
> 		
> __________________________________ 
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