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# PERL exists Function

## Syntax

exists EXPR

## Definition and Usage

Returns true if the specified hash or array key exists, regardless of the corresponding value, even if it.s undef. If EXPR is a subroutine, then exists will return 1 if the subroutine has been declared (but not necessarily defined), 0 if not.

## Return Value

- 0 if hash element or array index does not exist, or if the subroutine has not been declared

- 1 if hash element or array index does exist, or if the subroutine has not been declared

## Example

Following are the usage...

        print "Exists\n" 	if exists $hash{$key};
        print "Defined\n" 	if defined $hash{$key};
        print "True\n"      if $hash{$key};

        print "Exists\n" 	if exists $array[$index];
        print "Defined\n" 	if defined $array[$index];
        print "True\n"      if $array[$index];

        print "Exists\n" 	if exists &subroutine_name;
        print "Defined\n" 	if defined &subroutine_name;

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