JavaScript Shift () method

http://www.w3school.com.cn/jsref/jsref_shift.aspDefinition and Usage

The shift () method removes the first element from the array and returns the value of the first element.

Grammar

Arrayobject.shift ()

return value

The value of the original first element of the array.

Description

If the array is empty, then the shift () method will not take any action, returning the undefined value. Note that the method does not create a new array, but instead modifies the original arrayobject directly.

Hints and notes

Note: This method will change the length of the array.

Tip: To delete and return the last element of the array, use the Pop () method.

Example

In this example, we will create an array and delete the first element of the array. Note that this will also change the length of the array:

<script type= "Text/javascript" >var arr = new Array (3) arr[0] = "George" arr[1] = "John" arr[2] = "Thomas" Document.writ E (arr + "<br/>") document.write ( arr.shift() + "<br/>") document.write (arr) </script>

Output:

George,john,thomasgeorgejohn,thomas

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Shift ()

How to use Shift () to delete and return the first element of an array.

JavaScript Shift () method