map method
returns new array with the results of calling a provided function on every
element in this array.
Syntax
arr.map(callback[,
thisArg])
callback is a function that takes following
three arguments.
Argument
|
Description
|
currentValue
|
The
current element being processed in the array.
|
index
|
The
index of the current element being processed in the array.
|
array
|
The
array that map() is being applied to.
|
thisArg
Optional.
Value to use as this when executing callback.
Get new array by squaring element
/* Get new
array by squaring every element */
var arr2 =
arr1.map(function(value){
return value * value
});
Get new array by applying square root
var arr3 =
arr1.map(Math.sqrt);
map.html
<!DOCTYPE html> <html> <head> <title>Array map</title> </head> <body> <script type="text/javascript"> var arr1 = [2, 3, 5, 7]; displayArray(arr1); /* Get new array by squaring every element */ var arr2 = arr1.map(function(value) { return value * value }); displayArray(arr2); /* Get new array by applying square root on every element */ var arr3 = arr1.map(Math.sqrt); displayArray(arr3); function displayArray(array, arrayName) { document.write("<br />Elements in array " + arrayName + " are <br />"); array.forEach(function(value) { document.write(value + "<br />"); }); } </script> </body> </html>
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