We can count the number of elements in an array in Ruby using the
Array#length method.
{{code:php $numbers = array(1, 2, 3); print count($numbers); // => 3 }}
{{code:ruby numbers = [1, 2, 3] puts numbers.length # => 3 }}
An important gotcha to remember is that while we can skip elements in an array
in PHP, we cannot do so in Ruby. If you add a tenth element to an array, Ruby
will fill in the missing elements with nil.
{{code:php $numbers = array(1, 2); $numbers[10] = 3; print count($numbers); // => 3 }}
{{code:ruby numbers = [1, 2] numbers[10] = 3 puts numbers.length # => 11 }}
{{related: var/is_array strings/strlen }}