- The unshift() method, part of the JavaScript Array object, adds an element at the beginning of an array, and returns the length representing the number of elements in the updated collection:
// Declare array with two elements:
var arr = [ "learn", "JavaScript" ];
// Add new element, and store new length:
var newLength = arr.unshift("We");
// Check new length and content of array:
alert( newLength +"\n"+ arr.join(" ") );Note: use join() to "glue" pieces of an array into a string (with a space character, in this case).
- Here's a script that ignores the returned length, and prepends three new elements to an existing array, as simply as passing multiple arguments at the same time: (no need for a loop!)
var arr = [ 3, 4, 5, 6 ]; // Declare an array of 4 elements
// Pass the new elements to insert as arguments
arr.unshift( 0, 1, 2 );
// Display each element of the updated array on its own line:
alert( arr.join("\n") ); - The PHP equivalent to JavaScript's unshift() method is the array_unshift() function: it takes one or more elements to add as arguments, and returns the size of the new array.
$arr = array( 'learn', 'PHP' );
$newLength = array_unshift( $arr, 'We', 'decided', 'to' );
echo "Elements count is $newLength; content is:<br>";
print_r( $arr ); // Display each element Sister methods - array insertion and deletion:
• concat() adds elements or arrays at the end of an array, and returns a copy of the new array.
• unshift() adds an element to the start of an array ("prepends"), and returns the new length.
• push() adds an element to the end of an array ("appends"), and returns the new length.
• shift() removes the first element of an array, and returns its value.
• pop() removes the last element of an array, and returns its value.
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