rust functional programming

iterator

  • iter() Returns an iterator over the slice
  • into_iter() Creates a consuming iterator, that is, one that moves each value out of the vector
  • iter_mut() Returns an iterator that allows modifying each value.

flat_map

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/// Creates an iterator that works like map, but flattens nested structure.
///
/// The [`map`] adapter is very useful, but only when the closure
/// argument produces values. If it produces an iterator instead, there's
/// an extra layer of indirection. `flat_map()` will remove this extra layer
/// on its own.

Examples

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let words = ["alpha", "beta", "gamma"];
// chars() returns an iterator
let merged: String = words.iter()
                          .flat_map(|s| s.chars())
                          .collect();
assert_eq!(merged, "alphabetagamma");