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rubyhaskellfunctional-programming

Ruby array pattern matching

I am new to programming in Ruby and have seen that it has some functional capabilities. Was wondering if there is a way to pattern match on arrays; I am looking to accomplish the following:

split_string = str.split("_", 2)
fst = repo_branch_split.first
snd = repo_branch_split.second

in a Haskell-like manner:

split_string@(fst : snd) = str.split("_", 2)

Is there anything similar in ruby or not?

Solution

  • This is a parallel assignment in Ruby. You can assign an array to variables this way:

    fst, snd = str.split("_", 2)

    You can also achieve head / tail behavior from Haskell by assigning rest of the array to a single variable:

    head, *tail = "foo_bar_baz".split("_")
# head => "foo"
# tail => ["bar", "baz"]

    Without star in tail, it would assign only bar string and baz would "disappear".