Syntax:mixed public DsMap::reduce ($callback, $initial)
Parameter :This function takes two parameters as above and described below:
- $callback:This parameter contains a function that contains an element operation and storage in the transfer. This callback function contains three arguments, which are listed below:
- carry:contains the return value of the previous callback, or the initial value if this is the first iteration.
- key:it contains the key of the current iteration.
- value:contains the value of the current iteration.
- $initial:this parameter contains the initial carry value, which can be NULL.
Return value:This function returns the final value returned a callback function.The following programs illustrate the
Ds / Map::redu()function in PHP:
Program 1:
// Declare a new map $map = new DsMap ([ "a" = > 1, "b" = > 3, "c" = > five]); echo ( " Map Elements " ); print_r ( $map );
// callback function with downgrade echo ( "Element after performing operation" ); var_dump ( $map -> reduce ( function ( $carry , $key , $element ) { return $carry + $element + 2; }));
?> Exit:Map Elements DsMap Object ([0] = > DsPair Object ([key] = > a [value] = > 1) [1] = > DsPair Object ([key] = > b [value] = > 3) [2] = > DsPair Object ([key] = > c [value] = > 5)) Element after performing operation int (15)
Program 2:
// Declaring new map elements $map = new DsMap ([ "a" = > 10, " b " = > 20, "c" = > 3 0, "d" = > 40, "e" = > fifty]); echo ( " Original map elements " ); print_r ( $map ); $func_gfg = function ( $carry , $key , $element ) { return $carry * $element ; }; echo ( " Map after reducing to single element " );
// Using the redu() function var_dump ( $map -> reduce ( $func_gfg , 10));
?> Exit:Original map elements DsMap Object ([0] = > DsPair Object ([key] = > a [value] = > 10) [1] = > DsPair Object ([key] = > b [value] = > 20 ) [2] = > DsPair Object ([key] = > c [value] = > 30) [3] = > DsPair Object ([key] = > d [value] = > 40) [ 4] = > DsPair Object ([key] = > e [value] = > 50)) Map after reducing to single element int (120000000)
Link: https://www.php.net/manual/en/ds-map.reduce.php
