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PERL undef Function



Syntax

undef EXPR

undef


Definition and Usage

Undefines the value of EXPR. Use on a scalar, list, hash, function, or typeglob. Use on a hash with a statement such as undef $hash{$key}; actually sets the value of the specified key to an undefined value. If you want to delete the element from the hash, use the delete function.

Return Value

  • undef

Example

#!/usr/bin/perl -w

$scalar = 10;
@arrary = (1,2);

print "1 - Value of Scalar is $scalar\n";
print "1 - Value of Array is @array\n";

undef( $scalar );
undef( @array );

print "2 - Value of Scalar is $scalar\n";
print "2 - Value of Array is @array\n";

It will produce following results:

1 - Value of Scalar is 10
1 - Value of Array is
Use of uninitialized value in concatenation (.) or 
                         string at test.pl line 13.
2 - Value of Scalar is
2 - Value of Array is


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