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Perl Programming/Keywords/exists
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Perl exec exit Keywords
The exec keyword
exists returns true, if an expression that specifies an element of a hash exists, and the specified element in the hash has been initialized to any value (like undef).
Although exists can be called on arrays also, its behaviour strongly depends to the use of delete on arrays, having a much less clear behaviour.
Syntax
exists EXPRESSION
Examples
print "Exists\n" if exists $hash{$key};
print "Defined\n" if defined $hash{$key};
print "True\n" if $hash{$key};
See also
system
Perl exec exit Keywords