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JavaScript Array Object Methods – Part I

 

push() and reverse() ArrayObject Methods

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push()

push() method of an array object contrasts to the pop() method. push() method is used to add one or more elements to the array. This is added to the end of the array, changing the length of the array object. The new length is returned by the push() method.



General syntax of the push() method of the Array object of JavaScript:


arrayObject.push(element1,element2,....,elementn)


Here element1, element2,...., elementn represents the new elements to be added to the array object. It is required that at least element1 must be present. This means, in order for it to be added, there must be at least one element specified in argument of the push().


An example to understand this concept in detail:



<html>
   <
body>
      <
script type="text/javascript">
      
var exforsys = new Array(4)
       exforsys[0] = "Welcome"
       exforsys[1] = "To"
       exforsys[2] = "Exforsys"
       exforsys[3] = "Training"
       document.write(exforsys + "<br />")
       document.write(exforsys.push("Good Day") + "<br />")
       document.write(exforsys)         


      </script>
   </
body>
</
html>



The output of the code above will be:
 



Welcome,To,Exforsys,Training
5
Welcome,To,Exforsys,Training,Good Day


In the above example, the array object exforsys elements are first outputted and then the push() method with arguments as "Good Day" is used with the array object exforsys. This adds the element after the last element. Therefore, the length of the array changes to 5 and this is then outputted. As shown in the last result, the array is printed with the new elements added to it.


reverse()

As the name implies, the reverse() method of the Array object reverses the order of the elements in an array, using the first element as the last element and the last element as the first element. The original array is changed by using the reverse() method.


General syntax of the reverse() method of the Array object of JavaScript:


arrayObject.reverse()


An example to understand this concept in detail:



<html>
   <
body>
      <
script type="text/javascript">
         var exforsys = new Array(4)
         exforsys[0] = "Welcome"
         exforsys[1] = "To"
         exforsys[2] = "Exforsys"
         exforsys[3] = "Training"
         document.write(exforsys + "<br />")
         document.write(exforsys.reverse()
         + "<br />")
         


      </script>
   </
body>
</
html>


The output of the code above will be:



Welcome,To,Exforsys,Training
Training,To,Exforsys,Welcome



In the above example first the elements of the array object exforsys is printed as such and then the reverse() method is sued with the exforsys array object and so the first element "Welcome" is made as the last element and the last element "Training" is made as the last first element and changed array is printed




First Page: JavaScript Array Object Methods – Part I


Read Next: JavaScript Array Object Methods – Part II



 

 

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