数组转换为哈希

Question

I'm confused as to this behavior. Do I really need to split my array to make this work?

pry(main)> ary = ["foo", "bar"]
=> ["foo", "bar"]

pry(main)> Hash[ary]
=> {"f"=>"o", "b"=>"a"}

pry(main)> Hash["foo", "bar"]
=> {"foo"=>"bar"}

pry(main)> Hash[["foo", "bar"]]
=> {"f"=>"o", "b"=>"a"}

pry(main)> Hash[ary.split(",")]
=> {"foo"=>"bar"}

Answer 1

Tries 1 and 3 above are equivalent, passing a single one dimensional array to the constructor, which is not correct.

For this to work as you expect, you'd need to pass the parameters as separate arguments, or as a 2 dimensional array of pairs>

# Split the array into args (equivalent to example #2 above)
# equivalent to Hash[key1, val1, key2, val2]
Hash[*ary]

# or wrap the array in another array (an array of nested pairs)
# equivalent to Hash[[[key1,val1],[key2,val2]]]
Hash[[ary]]

The incorrect behavior you're seeing is presumably because the constructor expects an array of length-2 arrays, while you've passed an array of strings. It interprets arg[0] as the key for each pair, and arg[1] as the value, in this case f and o , b and a .