You can test with a regexp, which you can roll your own with something like (this is a fairly simple example): 
  if ( $var =~ /^-?\d+(\.\d+)?$/ ){
    # you have a float
  }

[download]
But I'd recommend checking out Regexp::Common::number which will cover many more cases.

In reply to Re: dependable way to test for a float by davidrw
in thread dependable way to test for a float by vindaloo

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