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## Replace `reduce` with `fold`

Unlike some languages, Rust's [reduce](https://doc.rust-lang.org/std/iter/trait.Iterator.html#method.reduce) returns an `Option`, requiring additional bytes to `unwrap` the output. However, Rust's [fold](https://doc.rust-lang.org/std/iter/trait.Iterator.html#method.fold) does not.

If you can find a suitable neutral initial value that will keep your output the same (such as the additive identity `0` for a sum, or the multiplicative identity `1` for a product, or the empty string `""` for string concatenation), then you can use `fold` instead of `reduce`. This does not need the output to be in an `Option` because supplying an initial value means there is no doubt over what the output should be for an empty input[^1], so `fold` returns the output directly.

```rust
println!("{}",(1..6).reduce(|a,b|a*b).unwrap());  // 120
println!("{}",(1..6).fold(1,|a,b|a*b));           // 120
```

[Test both on Rust Playground](https://play.rust-lang.org/?version=stable&mode=debug&edition=2024&gist=893954d3331f064003a0e047625dc581)


[^1]: The output that makes sense for an empty input will differ depending on the operation being carried out. The sum of an empty list of numbers is 0, but the product of an empty list of numbers is 1. Since `reduce` accepts an arbitrary function as the operation, and Rust cannot know what the appropriate output for an empty input would be for all functions, it returns `None` for an empty input.