# Solved: numpy random entries not repeat

In today’s world of data manipulation and analysis, one common problem that arises is generating non-repeating random entries using the widely popular Python library NumPy. This article aims to provide a comprehensive solution to this problem, delving deep into the inner workings of the code and exploring relevant libraries and functions.

NumPy is a powerful library that enables us to perform various mathematical and statistical operations on large multi-dimensional arrays and matrices. One of the important aspects of data analysis and machine learning is generating random numbers, which can be achieved using NumPy’s random module. In certain cases, we might need these random entries to be unique and non-repeating. Let’s explore how to achieve this using NumPy step by step.

First, let’s import the required library and discuss the solution to generate non-repeating random entries using NumPy.

```import numpy as np
```

## Generating Unique Random Numbers

The solution to generate non-repeating random entries lies in understanding the numpy.random module and utilizing its methods efficiently. In particular, the numpy.random.choice() function proves to be extremely useful in this scenario, as it can generate random samples from a given 1-D array with the option to prevent repetitions.

Let’s break down the code and understand how to generate unique random numbers.

```def unique_random_numbers(size, lower_limit, upper_limit):
unique_numbers = np.random.choice(np.arange(lower_limit, upper_limit), size, replace=False)
return unique_numbers

size = 10
lower_limit = 1
upper_limit = 101

unique_numbers = unique_random_numbers(size, lower_limit, upper_limit)
print(unique_numbers)
```
• The unique_random_numbers() function takes three parameters: the desired size of the array, the lower limit, and the upper limit for the random numbers. In this example, we aim to generate 10 unique random numbers between 1 and 100.
• Inside the function, we use the numpy.random.choice() method to randomly select elements from a range created by the numpy.arange() function. The replace=False argument ensures non-repeated entries within the array.
• After defining the function, we call it with the specified values and print the resulting array of non-repeating random numbers.

## Understanding numpy.random and numpy.arange

The numpy.random module is a powerful tool for generating random numbers and samples. Some commonly used functions within this module include numpy.random.rand(), numpy.random.randn(), and numpy.random.randint(). However, as previously mentioned, the function we need for this problem is numpy.random.choice().

numpy.arange() is a function within the NumPy library itself and is used to return an evenly spaced sequence of values within the specified range. It accepts three parameters: the start value, the stop value, and the step size. By default, the step size is 1.

## Application of Generating Unique Random Entries

Generating unique random entries has its practical uses in multiple real-world scenarios, such as:

• Shuffling data: Often used in machine learning, shuffling data helps in randomizing the order of data points, minimizing biases and enhancing model performance.
• Sampling without replacement: In statistics, non-repeated random sampling can be used to ensure a representative sample is taken from a larger population.
• Creating random assignments: Distributing tasks or resources among a group without repetition can be achieved through the use of unique random numbers.

In conclusion, generating non-repeating random entries using NumPy is simple and efficient using the numpy.random.choice() method. Understanding the numpy.random and numpy.arange functions, and their application empowers us in tackling an array of practical use cases in data analysis, machine learning, and beyond.

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