in reply to How to check if a scalar value is numeric or string?

Thanks to the sugestions above i have the function isnum: 
sub isnum ($) { $_[0] ^ $_[0] ? 0 : 1 }

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XORing a number gives zero, so the function returns 1. XORing a string gives a string of nulls, still a non-empty string, so the function returns 0

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Re^2: How to check if a scalar value is numeric or string?
by ibravos (Initiate) on Mar 09, 2012 at 11:02 UTC
    Correction: isnum('') returns 1, so here is a better version 
    sub isnum ($) {
    return 0 if $_[0] eq '';
    $_[0] ^ $_[0] ? 0 : 1
}

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