Syntax:DsSet public DsMap::keys (void)
Parameter: this function takes no parameters.Return Value:Returns a Ds / Set containing all the keys of the specified Map instance in the same order.Below the programs illustrate the Ds / Map::keys()function in PHP:Program 1:
// PHP program for illustrating the keys() function
$map
=
new
DsMap ([1 = >
" Geeks "
, 2 = >
"for"
,
3 = >
"Geeks"
]);
print_r (
$map
-> keys());
?>
Output:DsSet Object ([0] = > 1 [1] = > 2 [2] = > 3)
Program 2:
// PHP program to illustrate the keys() function
$map
=
new
DsMap ([
"first"
= >
"Geeks"
,
"second"
= >
"for"
,
"third"
= >
"Gee ks "
]);
print_r (
$map
-> keys());
?>
Output:DsSet Object ([0] = > first [1] = > second [2] = > third)
Link : http://php.net/manual/en/ds-map.keys.php /