The _.cat() method is used to concatenate zero or more arguments into one array.
Syntax:
_.cat(arg1, arg2, ...)
Parameters:
- Args: This method accepts n arguments to concatenate into a single array.
Return Value: This method returns a concatenated array.
Note: This method will not work in normal JavaScript because it requires the underscore.js contrib library to be installed.
underscore.js contrib library can be installed using npm install underscore-contrib –save
Example 1: In this example, we will concatenate 2 arrays.
Javascript
// Defining underscore contrib variable var _ = require('underscore-contrib'); // Array1 var arr1 = [1,2,3] // Array2 var arr2 = [4,5,6] // Concatenation var arr = _.cat(arr1, arr2); console.log("array 1 : "+ arr1); console.log("array 2 : "+ arr2); console.log("concatenated array : "+ arr); |
Output:
array 1 : 1,2,3 array 2 : 4,5,6 concatenated array : 1,2,3,4,5,6
Example 2: In this example, we will concatenate 2 numbers to form an array.
Javascript
// Defining underscore contrib variable var _ = require('underscore-contrib'); // Number 1 var num1 = 1 // Number 2 var num2 = 4 // Concatenation var arr = _.cat(num1, num2); console.log("num1 : "+ num1); console.log("num2 : "+ num2); console.log("concatenated array : "+ arr); |
Output:
num1 : 1 num2 : 4 concatenated array : 1,4
Example 3: In this example, we will concatenate 3 arrays.
Javascript
// Defining underscore contrib variable var _ = require('underscore-contrib'); // Array1 var arr1 = [1,2,3] // Array2 var arr2 = [4,5,6] // Array3 var arr3 = [7,8,9] // Concatenation var arr = _.cat(arr1, arr2, arr3); console.log("array 1 : "+ arr1); console.log("array 2 : "+ arr2); console.log("array 3 : "+ arr3); console.log("concatenated array : "+ arr); |
Output:
array 1 : 1,2,3 array 2 : 4,5,6 array 3 : 7,8,9 concatenated array : 1,2,3,4,5,6,7,8,9
Example 4: The _.cat() method will also work with the arguments object as if it were an array.
Javascript
// Defining underscore contrib variable var _ = require('underscore-contrib'); // Function function f(){ return _.cat(arguments, 4, 5, 6); } console.log("Array is : " + f(1,2,3)); |
Output:
Array is : 1,2,3,4,5,6
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