Other Useful Methods
Below are some array methods you may find useful for problem solving. There's no need to memorize. You'll learn by putting these methods into practice.
You've already seen length in action. It returns the number of elements in the array.
[1, 2, 3, "a", "b", "c"].length #=> 6
Try running the code. (Click the run button.)
sort sorts an array alphabetically or numerically. It requires that the array
be comprised entirely of numbers or strings. Otherwise the
interpreter won't know how to compare elements! Like many array methods, sort
has a counterpart that modifies the original array: sort!. A bang (!)
typically denotes methods that modify their receiver, so-called "dangerous"
methods.
[3, 1, 2].sort #=> [1, 2, 3]
["c", "a", "b"].sort #=> ["a", "b", "c"]
in_the_danger_zone = [3, 1, 2]
in_the_danger_zone.sort!
in_the_danger_zone #=> [1, 2, 3]
Try running the code. (Click the run button.)
reverse reverses the order of an array. reverse has a dangerous version:
reverse!.
[nil, false, "ranger danger"].reverse #=> ["ranger danger", false, nil]
the_dangerest_rangerest = [nil, false, "ranger danger"]
the_dangerest_rangerest.reverse!
the_dangerest_rangerest #=> ["ranger danger", false, nil]
Try running the code. (Click the run button.)
include? returns a boolean value indicating whether its argument is
included in the array.
["a", "b", "c"].include?("a") #=> true
["a", "b", "c"].include?(1) #=> false