Scanning an array of strings for match in Ruby

Question

I have an array:

a = ["http://design.example.com", "http://www.domcx.com", "http://subr.com"]

and then I want to return true if one of the elements in that array matches the string:

s = "example.com"

I tried with include? and any?.

a.include? s
a.any?{|w| s=~ /#{w}/}

I don't know how to use it here. Any suggestions?

the Tin Man · Accepted Answer · 2013-04-10 14:48:56Z

8

You can use any? like:

[
  "http://design.example.com",
  "http://www.domcx.com",
  "http://subr.com"
].any?{ |s| s['example.com'] }

Substituting your variable names:

a = [
  "http://design.example.com",
  "http://www.domcx.com",
  "http://subr.com"
]
s = "example.com"
a.any?{ |i| i[s] }

You can do it several other ways also, but the advantage using any? is it will stop as soon as you get one hit, so it can be much faster if that hit occurs early in the list.

answered Apr 10, 2013 at 14:48

the Tin Man

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3 Comments

the Tin Man Over a year ago

See str[matchstr]. "If a match_str is given, that string is returned if it occurs in the string." It returns nil if nothing is found, or the sub-string, effectively triggering the any? with a false/true result. It's part of the wonderfulness of Ruby.

Arup Rakshit Over a year ago

Thanks for the link,never reached to the middle of the cluster of methods :)

prabu Over a year ago

Thanks for the match str method. your logic works for me. I need to get very first element in an array list if it is return true. I have written like a.any?{ |i| p i unless i[s] }. Thanks.

Arup Rakshit · Accepted Answer · 2013-04-10 14:48:36Z

2

How is the below:

a=["http://design.example.com", "http://www.domcx.com", "http://subr.com"]
s= "sus"
p a.any? { |w| w.include? s } #=> false

a=["http://design.example.com", "http://www.domcx.com", "http://subr.com"]
s= "design.example"
p a.any? { |w| w.include? s } #=>true

a=["http://design.example.com", "http://www.domcx.com", "http://subr.com"]
s= "desingn.example"
p a.any? { |w| w.include? s } #=>false

a=["http://design.example.com", "http://www.domcx.com", "http://subr.com"]
s= "example"
p a.any? { |w| w.include? s } #=>true

a=["http://design.example.com", "http://www.domcx.com", "http://subr.com"]
s= "example.com"
p a.any? { |w| w.include? s } #=>true

answered Apr 10, 2013 at 14:48

Arup Rakshit

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