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Re: Equality operators

by mantadin (Beadle)
on Apr 25, 2006 at 11:40 UTC ( #545537=note: print w/replies, xml ) Need Help??

in reply to Equality operators

As '==' is the numeric equality operator, it doesn't make sense to use it for strings. For all Strings you should use eq instead of ==, ne instead of != and cmp instead of <=>.

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Re^2: Equality operators
by jkva (Chaplain) on Apr 25, 2006 at 11:41 UTC
    Mantadin, thank you. I am aware of this, however I am wondering why '1' == '1foo' evals to true while '1' eq 'foo1' does not.

      When converting strings to numbers, Perl only looks at the start of the string. '1foo' becomes 1 and 'foo1' becomes 0.


      "The first rule of Perl club is you do not talk about Perl club."
      -- Chip Salzenberg

      because strings are automatically converted to numbers when needed. '1foo' is converted to 1 and 'foo1' is converted to 0.

      Others have already explained how the conversion works, but if you want to see for yourself the number into which a string is coerced, add 0 to the string.

      print(0+'a', "\n"); # 0 print(0+'b', "\n"); # 0 print(0+'1', "\n"); # 1 print(0+'2', "\n"); # 2 print(0+'1foo', "\n"); # 1 print(0+'foo1', "\n"); # 0

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