Can anybody help me write a regular expression which could find all the instances of the following in a long string >
type="array" count="x" total="y"
where x and y could be any numbers from 1 to 100.
language is ruby.
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How important is the "1 to 100" bit? Must it not match numbers bigger than 100 at all?Jonathan– Jonathan2011-06-10 14:23:18 +00:00Commented Jun 10, 2011 at 14:23
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2 Answers
First, since we'll use the regex for a number twice, we'll save it as its own variable. Note that the number regex is comprised of three separate pieces: one-digit numbers, two-digit numbers, and three-digit numbers. This is a good rule of thumb to use when trying to make a regex to match a range of numbers. It's easy to get it wrong otherwise (allowing strings like "07").
Once you have the number regex, the rest is easy.
number = /[1-9]|[1-9][0-9]|100/
regex = /type="array" count="#{number}" total="#{number}"/
string.scan(regex)
8 Comments
Roberto Decurnex
@Jeff_Terrell The problem with the
match is that you will just get the match object and that match object will only contains the first match and not all of the occurrences.Roberto Decurnex
BTW, why are you upvoting this answer as it is right now. At least test it before please!
Jeff Terrell PhD
Good point, NeX. That wasn't what nEEbz asked for, was it? I've updated my code above. Thanks!
Roberto Decurnex
@Jeff_Terrell yup he was trying to "find all the instances". Looks much better now ;)
neeebzz
thanks; it works. can you tell me what exactly this notation do
#{} ? |
This will return an array of matches
long_string.scan(/type="array" count="(?:[1-9]\d?|100)" total="(?:[1-9]\d?|100)")