Comment by typesanitizer | Hacker News Reader

Comment by typesanitizer | Hacker News Reader

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> Some complaints also seem like a lack of experience using the language.

> In my experience, the two-value (explicit capacity) form of "make" is significantly _less_ common than the single-value form. Indeed, gripping through the stdlib shows "make([]T, n) is much more common than "make([]T, n, m)".

I've written a fair bit of C++, where this pattern is very common. IME in 95%+ of the cases, what one wants is a vector with a capacity without initializing it, because it will be filled up right away.

I'd argue that make([]T, n) is more common in actual Go code precisely because it has the shorter spelling, not because it has the exact desired semantics.

Ah. But this is writing C++ in Go instead of writing Go in Go.

In C++ I'd write something like

  std::vector<T> vector;
  vector.reserve(10);
  for (auto i = 0; i < 10; i++) {
    vector.push_back(...);
  }

but in Go I'd write

  vec := make([]T, 10)
  for i := 0; i < 10; i++ {
      vec[i] = ...
  }

Just like in Rust I might use iter().collect() or whatever.

I was curious what it looked like where I work, because I mostly encounter `make([]T, 0, n)` in codebases I've touched, so I did a quick grep...

And the results were roughly 6,000 cases of `make([]T, n)` vs 5,000 cases of `make([]T, 0, n)`, ignoring most generated files (afaict), allowing basically anything but `,` for `n`, and requiring `...)$` for regex simplicity. I didn't read all the results, but the couple hundred I did check in both looked reasonable, so it's probably not too inaccurate.

I'm not sure how representative that is of go code in general, but I think I can be reasonably confident in claiming that neither is a consistent preference.

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