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Array: length

Like strings, arrays have the property length. Here it returns the number of elements in the array:
var languages = [];
var len0 = languages.length;
languages[0] = 'C';
var len1 = languages.length;
languages[1] = 'C++';
var len2 = languages.length;
The empty array contains no elements. len0 is 0. Now we fill the array step by step. len1 is 1 and len2 is 2.

Exercise

Write a function getLastElement that takes an array and returns the last element of the array. getLastElement([1, 2]) should return 2.