join
The join method type converts an array to a string. As its name suggests, it
joins every element in the array, each of which is implicitly converted to a
string. join takes an optional argument: the separator. The separator is a
string that the method splices between every element in the joined array. By
default, there is no separator. The join method does not modify the original
array.
[1, 2, nil, 3].join #=> "123"
[1, 2, nil, 3].join(" ") #=> "1 2 3" <-note the extra space to accommodate nil
ex = [1, 2, 3]
ex.join(" joint ") #=> "1 joint 2 joint 3"
# ex is not modified
ex #=> [1, 2, 3]