Method filter()

Method filter

array filter(array arr, function fun, mixed ... extra)
mixed filter(mixed arr, void|mixed fun, void|mixed ... extra)

Description

Map a function over elements and filters.

Calls the given function fun for all elements in arr, and keeps the elements in arr that resulted in a non-zero value from the function.

arr can have any of the following types:

`array`	If fun is an array: `for (i=0; i<sizeof(arr); i++) { if (fun[i]) res += ({ arr[i]});` otherwise: `keep = map(arr, fun, @extra); for (i=0; i < sizeof(arr); i++) { if (keep[i]) res += ({ arr[i]});`
`multiset`	`(multiset)filter((array)arr, fun, @extra)`
`mapping\|program\|function`	`ind = indices(arr); val = values(arr); keep = map(val, fun, @extra); for (i=0; i<sizeof(keep); i++) if (keep[i]) res[ind[i]] = val[i];`
`string`	`(string)filter((array)arr, fun, @extra)`
`object`	if `arr->cast` , try in turn: `filter((array)arr, fun, @extra)` `filter((mapping)arr, fun, @extra)` `filter((multiset)arr, fun, @extra)`

Returns

Returns the same datatype as given, the exceptions are program and function that give a mapping back.

See also

map, foreach()