The Lodash _.frequencies() method takes an array and returns a mapping object whose keys are the values of the array’s elements and values are counts of that key appeared in that array.
Syntax:
_.frequencies( array );
Parameters: This method accepts a single parameter as mentioned above and described below:
- array: The given array from which mapping is to be created.
Return Value: This method returns a created mapping object.
Note: This will not work in normal JavaScript because it requires the lodash.js contrib library to be installed. Lodash.js contrib library can be installed using the following command:
npm install lodash-contrib
Example 1:
// Defining underscore lodash variable
var _ = require('lodash-contrib');
// Array
var array = ["Geeks", "Geeks", "GFG",
"Computer_Science_Portal",
"Geeks", "GFG"];
var obj = _.frequencies(array);
// Printing object
console.log("Original Array : ", array);
console.log("Frequency of elements : ", obj);
Output:
Original Array : ["Geeks", "Geeks", "GFG", "Computer_Science_Portal", "Geeks", "GFG"] Frequency of elements : Object {Computer_Science_Portal: 1, GFG: 2, Geeks: 3}
Example 2:
// Defining underscore lodash variable
var _ = require('lodash-contrib');
// Array
var array = [];
var obj = _.frequencies(array);
// Printing object
console.log("Original Array : ", array);
console.log("Frequency of elements : ", obj);
Output:
Original Array : []
Frequency of elements : Object {}
Example 3:
// Defining underscore lodash variable
var _ = require('lodash-contrib');
// Array
var array = [1, 1, 1, 1, 1, 1, 3,
3, 3, 4, 4, 4, 5, 5, 5,
6, 6, 6, 6, 7, 7, 8, 10];
var obj = _.frequencies(array);
// Printing array
console.log("Original Array : ", array);
console.log("Frequency of elements : ", obj);
Output:
Original Array : [1, 1, 1, 1, 1, 1, 3, 3, 3, 4, 4, 4, 5, 5, 5, 6, 6, 6, 6, 7, 7, 8, 10] Frequency of elements : Object {1: 6, 3: 3, 4: 3, 5: 3, 6: 4, 7: 2, 8: 1, 10: 1}
