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Lodash _.sampleSize


The lodash library provides a wide range of functions and utilities for working with arrays, objects, numbers, strings, and other data types in JavaScript. One of the functions available in the library is the _.sampleSize() method, which is designed to randomly select a specified number of values from an input collection or sequence.

The _.sampleSize() method takes two arguments: the collection or sequence to sample from, and the number of values to sample. It returns an array that contains a random selection of items from the input collection, up to the specified number.

Here is the basic syntax for using the _.sampleSize() method:

_.sampleSize(collection, [n=1])

In this syntax, collection can be an array, a string, or an object. If it is an object, only its values will be sampled. The [n=1] argument is optional and specifies the number of items to sample from the collection. If this argument is not provided, the default value of n is 1.

For example, to select two random characters from a string, you could use the following code:

const str = 'abcdefghijklmnopqrstuvwxyz';
const randomChars = _.sampleSize(str, 2);
// output: ["j", "f"]

In this example, the str string contains all of the lowercase letters of the alphabet. The _.sampleSize() method is used to select two random characters from this string, which are returned as an array (["j", "f"]).

Similarly, you can use the _.sampleSize() method to select a random subset of items from an array:

const arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
const randomItems = _.sampleSize(arr, 3);
// output: [5, 2, 8]

In this example, the arr array contains the numbers 1 through 10. The _.sampleSize() method is used to select three random numbers from this array, which are returned as an array ([5, 2, 8]).

By default, the _.sampleSize() method uses a built-in random number generator to select items from the input collection. However, you can also pass in your own custom random number generator function as a third argument to the method. This allows you to control how the selection process is performed, and can be useful if you need to create deterministic test cases or other specialized applications.

Overall, the _.sampleSize() method is a powerful and convenient way to select a random subset of values from a collection or sequence in JavaScript. It is easy to use, customizable, and provides consistent and reliable results across different platforms and environments.