Asp Forum - Re: Variable substitution in a regex

Steve Callaway

5/18/2005 12:53:00 PM

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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1 Answer

dblack

5/18/2005 1:19:00 PM

comp.lang.ruby

Re: Variable substitution in a regex

Steve Callaway

dblack

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