You could use randomElement()

'user_id' => $faker->randomElement([1, 3]),

https://github.com/fzaninotto/Faker#fakerproviderbase

You could use regexify and and this let's you control what characters could be in the randomly generated string like this:

<?php

use Faker\Generator as Faker;

$factory->define(App\User::class, function (Faker $faker) {
    return [
        'name' => $faker->regexify('[A-Za-z0-9]{' . mt_rand(4, 20) . '}'),
    ];
});

Another option is $faker->realText(mt_rand(4, 20))

The factory is the real issue here not the faker. Calling of factory I mean.

Let's say you have User and User_Information model for example since you have not mention any models in your question above.

I assume you call the factory like below in which it creates a model one by one separately up to 10 that makes unique() of faker useless.

\App\Models\User_Information::factory()->create(10);

My solution to this problem is to use a loop to make unique() functional.

$max = 10;
for($c=1; $c<=$max; $c++) {
    \App\Models\User_Information::factory()->create();
}

NOTE: $max must not be greater to User::count(), else it will return an OverflowException error.

Faker offers a couple of methods that let you replace placeholders in a given string with random characters:

• lexify - takes given string and replaces ? with random letters
• asciify - takes given string and replaces * with random ascii characters
• numerify - takes given string and replaces # with random digits
• bothify - combines the lexify and numerify

You could try to use one of them, depending on the requirements you have for that random string you need. asciify uses the largest set of characters as replacement so using that one makes most sense.

The following will give you a random string of 20 ascii characters:

$faker->asciify('********************')

Update 2023 for v8

Now moved to https://github.com/faker-js/faker, they changed it again:

faker.number.int(options: number | {
  max: number,
  min: number
} = {}): number
faker.number.int() // 2900970162509863
faker.number.int(100) // 52
faker.number.int({ min: 1000000 }) // 2900970162509863
faker.number.int({ max: 100 }) // 42
faker.number.int({ min: 10, max: 100 }) // 57

source: https://fakerjs.dev/api/number.html#int

Update 2021

Latest versions changed location of the function from faker.random.number to faker.datatype.number, https://github.com/Marak/faker.js/issues/1156

Original answer

You need to give an object to the function:

faker.datatype.number({
    'min': 10,
    'max': 50
});

So if you just pass a number, it will set it as the max value. The min value is 0 by default.

This is the implementation of the number function :

this.number = function (options) {

    if (typeof options === "number") {
      options = {
        max: options
      };
    }

    options = options || {};

    if (typeof options.min === "undefined") {
      options.min = 0;
    }

    if (typeof options.max === "undefined") {
      options.max = 99999;
    }
    if (typeof options.precision === "undefined") {
      options.precision = 1;
    }

    // Make the range inclusive of the max value
    var max = options.max;
    if (max >= 0) {
      max += options.precision;
    }

    var randomNumber = options.precision * Math.floor(
      mersenne.rand(max / options.precision, options.min / options.precision));

    return randomNumber;

  }