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Anyone have examples where fold leads to easier to read code than a for loop in Rust?

• Mond_ 2y ago
  I find `foo.iter().map(|x| x.bar()).collect()` almost always easier to read and better at expressing intent than a for loop. The other direction is more interesting to me: Those are the awkward cases where people sometimes overdo it with the functional iterator heavy style.
• ironhaven 2y ago
  I have used fold for converting strings to a bitset in advent of code let string = "ewfsan"; let bitset = string.bytes().fold(0u32 |acc, ch| acc | 1 << (ch - b'a')); This is a idiom that I have used many times so this being more consice than a for loop is a plus Of course if you have never seen a syntax before it will make less sense that anything you have seen before
  • bippihippi1 2y ago
    afair I've mostly only used fold when doing maths not covered by the standard sum or product. Fold is similar to map reduce but it's just one expression.
• kccqzy 2y ago
  Readability is subjective. I personally find fold almost always more readable than a for loop when the accumulator variable has a simple type. This is because merely seeing fold can already telling me several things: it will iterate over the entire collection without early exits like "break" in a loop; the data dependency between each iteration is made clear into a single variable. I find it slightly difficult to read when the accumulator variable actually has multiple parts, like a complicated tuple. It's worse when part of the accumulator is a bool indicating whether it's finished; that's just a poor emulation of "break" in a for loop.