> For the complete documentation index, see [llms.txt](https://trizen.gitbook.io/sidef-lang/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://trizen.gitbook.io/sidef-lang/programming_tasks/f/filter.md).

# Filter

```ruby
var arr = [1,2,3,4,5]

# Creates a new array
var new = arr.grep {|i| i.is_even }
say new    # => [2, 4]

# Destructive (at variable level)
arr.grep! {|i| i.is_even }
say arr    # => [2, 4]
```