Regex Non Greedy Match

ruby-talk
1

Hello,

I am trying to get a non-greedy match, but am unable to do so. What may
I be doing wrong? Please help.

···

======
Code:

puts

str1 = "Hi, @[Subject:13|My_Subject]"
str2 = "Hi, @[Subject:13|My_Subject], and @[Subject:45|Your_Subject]"

re = /@\[Subject:\d+\|(.*)\]/

# works fine, grabs the matching pattern
p " ... this works fine ..."
p str1.scan(re).flatten

# why does this not grab the two patterns as an array?
# how to avoid the greedy match?
# that is, how to make it a non-greedy match?
puts
p " ... this does not work fine; how to avoid the greedy match? ..."
p str2.scan(re).flatten

puts

========
Output:

" ... this works fine ..."
["My_Subject"]

" ... this does not work fine; how to avoid the greedy match? ..."
["My_Subject], and @[Subject:45|Your_Subject"]

Thanks very much!
Naga Vijay

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2

re = /@\[Subject:\d+\|(.*)\]/

try :
re = /@\[Subject:\d+\|(.*?)\]/

test :
str2.scan re
=> [["My_Subject"], ["Your_Subject"]]

···

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3

In this case we can also use a character class which excludes closing
square bracket:

irb(main):004:0> [str1,str2].each {|s| printf "%s -> %p\n", s,
s.scan(/\[Subject:\d+\|([^\]]*)\]/)}
Hi, @[Subject:13|My_Subject] -> [["My_Subject"]]
Hi, @[Subject:13|My_Subject], and @[Subject:45|Your_Subject] ->
[["My_Subject"], ["Your_Subject"]]

irb(main):005:0> [str1,str2].each {|s| printf "%s -> %p\n", s,
s.scan(/\[Subject:\d+\|([^\]]*)\]/).flatten}
Hi, @[Subject:13|My_Subject] -> ["My_Subject"]
Hi, @[Subject:13|My_Subject], and @[Subject:45|Your_Subject] ->
["My_Subject", "Your_Subject"]

Kind regards

robert

···

On Wed, Aug 29, 2012 at 3:48 AM, Regis d'Aubarede <lists@ruby-forum.com> wrote:

re = /@\[Subject:\d+\|(.*)\]/

try :
re = /@\[Subject:\d+\|(.*?)\]/

test :
str2.scan re
=> [["My_Subject"], ["Your_Subject"]]

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4

Robert Klemme wrote in post #1073731:

···

On Wed, Aug 29, 2012 at 3:48 AM, Regis d'Aubarede <lists@ruby-forum.com> > wrote:

re = /@\[Subject:\d+\|(.*)\]/

try :
re = /@\[Subject:\d+\|(.*?)\]/

test :
str2.scan re
=> [["My_Subject"], ["Your_Subject"]]

In this case we can also use a character class which excludes closing
square bracket:

irb(main):004:0> [str1,str2].each {|s| printf "%s -> %p\n", s,
s.scan(/\[Subject:\d+\|([^\]]*)\]/)}
Hi, @[Subject:13|My_Subject] -> [["My_Subject"]]
Hi, @[Subject:13|My_Subject], and @[Subject:45|Your_Subject] ->
[["My_Subject"], ["Your_Subject"]]

irb(main):005:0> [str1,str2].each {|s| printf "%s -> %p\n", s,
s.scan(/\[Subject:\d+\|([^\]]*)\]/).flatten}
Hi, @[Subject:13|My_Subject] -> ["My_Subject"]
Hi, @[Subject:13|My_Subject], and @[Subject:45|Your_Subject] ->
["My_Subject", "Your_Subject"]

Kind regards

robert

Excellent! Thanks very much, Robert!

Naga Vijay

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Posted via http://www.ruby-forum.com/\.