Function filter #
Filter the items in an array or one dimensional matrix.
The callback is invoked with three arguments: the current value, the current index, and the matrix operated upon. Note that because the matrix/array might be multidimensional, the “index” argument is always an array of numbers giving the index in each dimension. This is true even for vectors: the “index” argument is an array of length 1, rather than simply a number.
Syntax #
math.filter(x, test)
Parameters #
| Parameter | Type | Description |
|---|---|---|
x |
Matrix | Array | A one dimensional matrix or array to filter |
test |
Function | RegExp | A function or regular expression to test items. All entries for which test returns true are returned. When test is a function, it is invoked with three parameters: the value of the element, the index of the element, and the matrix/array being traversed. The function must return a boolean. |
Returns #
| Type | Description |
|---|---|
| Matrix | Array | Returns the filtered matrix. |
Throws #
Type | Description —- | ———–
Examples #
function isPositive (x) {
return x > 0
}
math.filter([6, -2, -1, 4, 3], isPositive) // returns [6, 4, 3]
math.filter(["23", "foo", "100", "55", "bar"], /[0-9]+/) // returns ["23", "100", "55"]
