Perl by Example - 02

5.5. Hash (Associative Array) Functions

5.5.1. The keys Function

The keys function returns, in random order, an array whose elements are the keys of a hash (see "The values Function" and "The each Function").

Format keys(ASSOC_ARRAY) keys ASSOC_ARRAY Example 5.53. (In Script) # The keys function returns the keys of a hash 1 %weekday= ( '1'=>'Monday', '2'=>'Tuesday', '3'=>'Wednesday', '4'=>'Thursday', '5'=>'Friday', '6'=>'Saturday', '7'=>'Sunday', ); 2 foreach $key ( keys(%weekday) ){print "$key ";} print "\n"; 3 foreach $key ( sort keys(%weekday) ){print $key ;} print "\n"; (Output) 2 7 1 2 3 4 5 6 3 1 2 3 4 5 6 7 Explanation The hash %weekday is assigned keys and values. For each value in %weekday, call the keys function to get the key. Assign the key value to the scalar $key and print it in random order. Now the keys are sorted and printed.