---
title: filter_map() in Rust
visibility: public
glu:
  - bash
  - bash run.sh
---
One of the things that was really nice to discover in the Rust iterator trait was the `filter_map()` method. It really simplifies a lot of common situations where you are creating optional items and immediately want to filter out the `None`s.

```rust
// main.rs

fn main() {
	let original = vec![1, 2, 0, 3];
	let filter_mapped: Vec<_> = original
	  .iter()
	  .filter_map(|n| 360_i32.checked_div(*n))
	  .collect();

	let longhand: Vec<_> = original
		.iter()
		.map(|n| 360_i32.checked_div(*n))
		.filter(|n| n.is_some())
		.map(|n| n.unwrap())
		.collect();

	// Should produce same results, but we got the first one
	// with much nicer ergonomics. Isn't that nice?
	println!("filter_mapped: {:?}", filter_mapped);
	println!("longhand: {:?}", longhand);
}
```

### And to compile and run this example:

```bash
# run.sh
rustc main.rs && ./main
```