What is the "=~" operator in Ruby?

Question

I saw this on a screencast and couldn't figure out what it was. Reference sheets just pile it in with other operators as a general pattern match operator.

Answer 1

Well, the reference is correct, it is the "matches this regex" operator.

if var =~ /myregex/ then something end

Answer 2

It matches string to a regular expression.

'hello' =~ /^h/ # => 0

If there is no match, it will return nil. If you pass it invalid arguments (ie, left or right-hand sides are not correct), it will either throw a TypeError or return false.

Answer 3

I believe this is a pattern matching operator used with regex.

Answer 4

Regular expression string matching. Here's a detailed list of operators: http://phrogz.net/programmingruby/tut_expressions.html#table_7.1

Answer 5

From ruby-doc :

str =~ obj => fixnum or nil

Match—If obj is a Regexp, use it as a pattern to match against str,and returns the position the match starts, or nil if there is no match. Otherwise, invokes obj.=~, passing str as an argument. The default =~ in Object returns false.

"cat o' 9 tails" =~ /\d/   #=> 7
"cat o' 9 tails" =~ 9      #=> false

Answer 6

Regular expression string matching:

puts true if url =~ /google.com/

You can read '=~' as 'is matching'.