- JavaScript Array is like an empty box that can be used to store different information.
- It’s a temporary place to store many values.
- Array is a piece of memory allocated to store a variety of information.
- Arrays are defined using keyword var in JavaScript. You can assign any name to array, just like you can place any name on your empty box.
- Arrays values are saved in a stack format.
- Rules for naming arrays are similar to rule for naming variables.
Syntax for creating Arrays:
var NAME_OF_ARRAY = [“ARRAY VALUE 1”, “ARRAY VALUE 2”, “ARRAY VALUE 3”];
Another way to create an array is to use keyword let
let NAME_OF_ARRAY = [“ARRAY VALUE 1”, “ARRAY VALUE 2”, “ARRAY VALUE 3”];
- var or let is keyword for creating array
- NAME_OF_ARRAY can be any name of your choice.
- The square brackets [ ] shows the multiple values of an array.
- Array values are separated by commas
- Array values can be text, html or a code.
Example of JavaScript Array
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<script type="text/javascript"> var animals = ["cow", "dog", "cat"]; </script> |
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<script type="text/javascript"> let animals = ["cow", "dog", "cat"]; </script> |
Another Syntax for creating Arrays:
var NAME_OF_ARRAY = new Array(“ARRAY VALUE 1”, “ARRAY VALUE 2”, “ARRAY VALUE 3”);
Another way to create an array is to use keyword let
letNAME_OF_ARRAY = new Array(“ARRAY VALUE 1”, “ARRAY VALUE 2”, “ARRAY VALUE 3”);
- var or let is keyword for creating array
- new is a constructor that can be used to create an Array
- the word Array is also a keyword
- NAME_OF_ARRAY can be any name of your choice.
- The parenthesis ( ) shows the multiple values of an array.
- Array values are separated by commas
- Array values can be text, html or a code.
Example of JavaScript Array
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<script type="text/javascript"> var animals = new Array("cow", "dog", "cat"); </script> |
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<script type="text/javascript"> let animals = new Array("cow", "dog", "cat"); </script> |
- In above example we have created an array called animals and then saved value cow on position zero, dog on position one and cat on position two.
- In array values are stacked from position 0 to any position.
- Each element gets a numeric index automatically assigned to it.
- Indexes are start from zero.
The above example can also be coded in an another way
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<script type="text/javascript"> var animals = new Array(); animals[0] = "this is array value one" animals[1] = "this is array value two" animals[2] = "this is array value three" animals[3] = "this is array value four" </script> |
- In above example we are using ArrayName[Value Position] syntax.
- animals[0] represents the zero position of array
Some functions of Array
- Use arrayName.length to access the number of elements in the array
- Last element of the array has an index of arrayName.length -1
- Arrays have many inbuilt functionalities like .pop(), .push(),.shift() etc
Rules for Naming Arrays
- Variable names are case sensitive
- Variable names cannot start with numbers
- Variable names cannot contain spaces
- Variable names can contain letters, numbers, $, _
How to read array values
document.write is one of the methods for retrieving values stored in an array.
Syntax for reading values of an array
document.write(ArrayName[Value Index]);
Example of reading values of an array
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<script type="text/javascript"> var animals = new Array("cow", "dog", "cat"); document.write(animals[0]) document.write(animals[1]) document.write(animals[2]) //another way of reading values of an array document.write(animals[0] + "<BR>" + animals[1] + "<BR>" + animals[2] + "<BR>") </script> |