var a = []; // An empty array var b = [1, 2, 3]; b.length // Note: length is NOT a method // 3 // Appends elements to an array, and returns the new length a.push(4); // 1 // a = [4] a.push(5, 6); // 3 // a = [4, 5, 6] // Merge two arrays. // This method will NOT affect the original arrays b.concat(a); // [1, 2, 3, 4, 5, 6] // a = [4, 5, 6] // b = [1, 2, 3] var c = b.concat(a, [7], [8, 9, 10]); // a = [4, 5, 6] // b = [1, 2, 3] // c = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] // Removes the last element, and returns that element c.pop(); // 10 // c = [1, 2, 3, 4, 5, 6, 7, 8, 9] // Removes the first element, and returns that element c.shift(); // 1 // b = [2, 3, 4, 5, 6, 7, 8, 9] // Add elements to the beginning of the array, // and returns the new length c.unshift(1); // 9 // c = [1, 2, 3, 4, 5, 6, 7, 8, 9] c.unshift(-1, 0); // 11 // c = [-1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9] // Array can have mixed types of elements c = [1, 2, '3', 'a', 'b', true];
The versatile splice method adds and/or deletes elements to/from an array, and returns the deleted elements.
array.splice( index, count, element1, ..., elementN )
var c = [1, 2, '3', 'a', 'b', true]; // Deletes 1 element starting at the element of index 2 (0-based), // and returns the deleted elements c.splice(2, 1); // ['3'] // c = [1, 2, 'a', 'b', true] // Deletes 2 elements starting at the element of index 1 (0-based), // and returns the deleted elements c.splice(1, 2); // [2, 'a'] // c = [1, 'b', true] // Deletes 1 elements starting at the element of index 1 (0-based), // Inserts 'A' and 'B', // and returns the deleted elements c.splice(1, 1, 'A', 'B') // ['b'] // c = [1, 'A', 'B', true] // Inserts 'X' at index 1 c.splice(1, 0, 'X'); // [] Didn't delete anything // c = [1, 'X', 'A', 'B', true]
