Php array map class method

Javascript php array map class method code example

Here we are checking if the element of the array is EVEN or ODD and storing the result in new array using map method. The method is called for every element of the array and the result of the operation is mapped to the corresponding index in the new array.

JavaScript Array map()

Introduction to JavaScript Array map()

Map() is one of the utilities present in the JavaScript libraries to build an array by calling out a given operation to be performed on every element on the existing array. The method is called for every element of the array and the result of the operation is mapped to the corresponding index in the new array. Map() does not execute for the arrays that consist of no elements. The result is a new array with the same length where the existing elements being undisturbed thus also called non-mutating.

Syntax of JavaScript Array map():

Parameters of above syntax:

1. Method: This is the required parameter of this method of Map() function as it constitutes the call to the operation need to be performed on every element of the array to create the new array.

This method will pass below variables as arguments to call the function:

• currentValue: The current value of the array one by one is sent as arguments to call the method. This is one of the important argument of the method.
• index: The index of the current element is optional to be sent as argument.
• array: This refers to the reference variable to the array.

2. thisVal: This is also an optional parameter that is used to store the reference to the value being passed as parameter.

How JavaScript Array map() Method works?

Map Method is one of the utilities present in the JavaScript libraries that helps to store the result of an operation performed on each element of the array to a new array at the corresponding index. This method has specifications in ECMAScript(ECMA-262) in Array libraries. This method requires the function of the operation to be performed on the elements of the array as one of its arguments. Other arguments, like thisVal is an optional parameter that is by default declared as “Undefined” if not passed.

This method creates a new array with the same length as of the existing array. Then it performs the function call to the operation to be performed with passing the elements of the array one by one as the currentVal parameter. The result of the operation is stored at the index being passed as an argument or by default the index of the element in an existing array. Since the length of the existing array is considered to create a new array, this method does not operate if there are no elements in the array. Thus this method must not be called for an empty array.

Examples of JavaScript Array map()

Given below are the examples of JavaScript Array map():

Example #1

Here we are checking if the element of the array is EVEN or ODD and storing the result in new array using map method.

Check if the Number is odd or Even

<script>
varnumArr = [65, 44, 77, 90,12];
varresArray = numArr.map(checkEvenOrOdd)
function checkEvenOrOdd(num) <
if(num%2 ==0) <
return num.toString().concat(» is EVEN \n»);
>
else <
return num.toString().concat(» is ODD \n»);
>
>
document.getElementById(«demo»).innerHTML = resArray;

Here, map() calls checkEvenOrOdd method for each element of the array passed in num variable and the result is stored at the corresponding index in the resArray .

Example #2

Here we have names of the students of the class and their marks and we need to print the Result out .

After clicking on the button:

Here, getMarks method is called in map method to get the result in presentable manner which gets out once we press the button.

Example #3

Here we will see to print the factorial of numbers in the array using map method.

Factorial using Map Method

Here, we saw map method called myFunction for each member of the array numbers and print the result of it that is factorial of each number in new array resArray.

Conclusion

Map function helps to generate the new array and storing the results of the operation performed on each element of another array at the same index without any alteration made to the elements of the existing array. This function needs only one compulsory parameter to be passed as its argument is the operation to be performed on the elements.

Final thoughts

This is a guide to JavaScript Array map(). Here we discuss the introduction, how JavaScript Array map() Method works? and examples respectively. You may also have a look at the following articles to learn more –

JavaScript Array map() Method, Definition and Usage. map () creates a new array from calling a function for every array element. map () calls a function once for each element in an array. map () does not execute the function for empty elements. map () does not change the original array. Code samplevar numbers = [4, 9, 16, 25];function myFunction() Feedback

Call class method in the Array.map()

You can pass this scope as a second parameter to the map function, like this:

MyClass.prototype.another_method = function() < this.another.map(function(el) < this.some_method(el); >, this); // added this >

JavaScript Array map() | How JavaScript Array map(), Map Method is one of the utilities present in the JavaScript libraries that helps to store the result of an operation performed on each element of the array to a new array at the corresponding index. This method has specifications in ECMAScript(ECMA-262) in Array libr…

JavaScript Array map()

Examples

Return a new array with the square root of all element values:

Multiply all the values in an array with 10:

const numbers = [65, 44, 12, 4];
const newArr = numbers.map(myFunction)

function myFunction(num) <
return num * 10;
>

Definition and Usage

map() creates a new array from calling a function for every array element.

map() calls a function once for each element in an array.

map() does not execute the function for empty elements.

map() does not change the original array.

See Also:

Syntax

Parameters

Parameter	Description
function()	Required. A function to be run for each array element.
currentValue	Required. The value of the current element.
index	Optional. The index of the current element.
arr	Optional. The array of the current element.
thisValue	Optional. Default value undefined . A value passed to the function to be used as its this value.

Return Value

More Examples

Get the full name for each person:

function getFullName(item) <
return [item.firstname,item.lastname].join(» «);
>

Related Pages:

Browser Support

map() is an ECMAScript5 (ES5) feature.

ES5 (JavaScript 2009) fully supported in all browsers:

Chrome	IE	Edge	Firefox	Safari	Opera
Yes	9-11	Yes	Yes	Yes	Yes

Javascript — Call class method in the Array.map(), Thanks for contributing an answer to Stack Overflow! Please be sure to answer the question.Provide details and share your research! But avoid …. Asking for help, clarification, or responding to other answers.

Can a method be used as an array_map function

Yes, you can have callbacks to methods, like this:

array_map(array($instance, 'fun'), $ar) 

see the callback type in PHP’s manual for more info

array_map('Class::method', $array) 

Actually, you need to know the definition of Callback, please kindly refer to the following code:

 // An example callback method class MyClass < static function myCallbackMethod() < echo 'Hello World!'; >> $myArray = [1, 2, 3, 4]; // Type 1: Simple callback array_map('my_callback_function', $myArray); // Type 2: Static class method call array_map(array('MyClass', 'myCallbackMethod'), $myArray); // Type 3: Object method call $obj = new MyClass(); array_map(array($obj, 'myCallbackMethod'), $myArray); // Type 4: Static class method call (As of PHP 5.2.3) array_map('MyClass::myCallbackMethod', $myArray); // Type 5: Relative static class method call (As of PHP 5.3.0) class A < public static function who() < echo "A\n"; >> class B extends A < public static function who() < echo "B\n"; >> array_map(array('B', 'parent::who'), $myArray); // A ?> 

JavaScript Array map() Method, Definition and Usage. map () creates a new array from calling a function for every array element. map () calls a function once for each element in an array. map () does not execute the function for empty elements. map …

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How to Use the array_map Function in PHP With Examples

Sajal Soni Last updated Apr 16, 2021

In this quick article, we’ll discuss the array_map function in PHP. Basically, we’ll go through the syntax of the array_map function and demonstrate how to use it with real-world examples.

The array_map function allows you to apply a callback function to transform elements of an array. It’s really useful when you want to perform a specific operation on every element of an array. Apart from that, it also allows you to combine multiple arrays into a single multidimensional array.

Instead of iterating through all the array elements with the foreach construct to perform a specific operation on them, you should prefer the array_map function, which is built specifically for this.

Syntax of the array_map Function

In this section, we’ll go through the syntax of the array_map function to understand how it works.

Let’s have a look at the syntax of the array_map function:

array_map ( callable|null $callback , array $array , array . $arrays ) : array 

The first argument is the callback function, which is called when the array_map function iterates over the elements of an array. It could be a user-defined function or a class method in the callable form.

The second argument is the source array on which the callback function will run.

In most cases, you would only need these two arguments. But the array_map function allows you to pass additional array arguments that are passed as arguments to the callback function. They will all be combined into one multi-dimensional array in the output. It’s interesting that you can pass null as the callback, and array_map just performs a zip operation on the source arrays. I’ll demonstrate this with a couple of real-world examples in the next section.

The array_map function returns an array of all values processed by the callback function.

In the next section, we’ll go through a couple of real-world examples to understand how the array_map function works.

Real-World Examples

In this section, we’ll discuss how to use the array_map function in different ways.

How to Lowercase an Array

This is one of the most basic and useful examples. When you want to perform a specific operation on all the elements of an array, the array_map function is the way to go!

function lowercase($element) 

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