array_reduce Iteratively reduce the array to a single value using a callback function &reftitle.description; mixedarray_reduce arrayarray callablecallback mixedinitial&null; array_reduce applies iteratively the callback function to the elements of the array, so as to reduce the array to a single value. &reftitle.parameters; array The input array. callback mixedcallback mixedcarry mixeditem carry Holds the return value of the previous iteration; in the case of the first iteration it instead holds the value of initial. item Holds the value of the current iteration. initial If the optional initial is available, it will be used at the beginning of the process, or as a final result in case the array is empty. &reftitle.returnvalues; Returns the resulting value. If the array is empty and initial is not passed, array_reduce returns &null;. &reftitle.examples; ]]> &reftitle.seealso; array_filter array_map array_unique array_count_values