Fill array in Python

3000 explained code solutions for 75 technologies


import numpy as np

array = np.empty(10)
array.fill(5)ctrl + c
import numpy as np

load Numpy module for Python

.empty

generate empty Numpy array of the specified shape

10

we're creating empty array of 10 elements

.fill

fill array with specified value

5

we're going to fill our array with values of 5



An array is one of the fundamental data structures in Python. It stores elements in a contiguous memory location and each element can be accessed using its respective index. In Python, the numpy library is used to implement array data structures. Lists are also another data structure that mimics an array in Python.

In this tutorial, we will discuss different methods to fill array with random numbers in Python.

We can create an array of our desired shapes. Sometimes, we may require dummy arrays for some calculations. We can create an array filled with such dummy values since the numpy library also implements a random module to generate random numbers.

Ways to fill array with random numbers in Python

Let us now discuss how to fill array with random numbers in Python.

Using the numpy.random.randint() function to fill array with random numbers in Python

As discussed earlier, the numpy library has a random module that can help in generating random numbers for numpy arrays. The randint() function can be used to generate an array of the required size and fill array with random numbers in Python.

We need to remember the three main parameters. The first two parameters are the low and high values. The function will select a random integer between this range. The third parameter is the numpy0 parameter which specifies the shape of the final array.

See the following example.

Using the numpy.random.randint() function

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import numpy as np

arr = np.random.randint(0,10,10)

print(arr)    

 

Output:

[3 8 1 0 4 2 4 7 0 3]

In the above example, we generate random numbers between 0 to 10 and fill it in a one-dimensional array of length ten.

Using the numpy1 function to fill array with random numbers in Python

The numpy2 offer a new way to generate and work with random numbers. It uses an additional numpy3 to spawn such random bits and manage their states. To initiate a new numpy4, we use the numpy5 constructor.

After this, we can use the numpy1 function to generate random numbers and fill array with random numbers in Python.

We need to specify the low, high, and numpy0 values in this function as we did in the previous method.

For example,

Using the Generator.integers() function

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import numpy as np

g = np.random.default_rng()

arr = g.integers(0,5,10)

print(arr)

 

Output:

[0 2 1 1 1 0 1 1 3 0]

Further reading:

Generate random number between 0 and 1 in Python

Read more →

Get random boolean in Python

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Using the random0 function to fill array with random numbers in Python

As discussed in the first section, lists in Python also mimic an array. We can fill lists with random numbers using the random module in Python. We will use list comprehension along with the random0 function to fill array with random numbers in Python.

We will use the random0 function to generate a random number between a given range. We will use the list comprehension method that loops over this function the required number of times, creating a new list of the required length.

See the following code.

Using the random.randint() function

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import random

arr = [random.randint(1,5) for _ in range(10)]

print(arr)    

 

Output:

[4, 2, 5, 3, 2, 2, 3, 3, 4, 2]

Conclusion

To conclude, in this tutorial we discussed different methods to fill array with random numbers in Python. Essentially, we were creating arrays with random numbers. For this, we used numpy arrays and lists.

For numpy arrays, we had two methods. The first was the traditional numpy.random.randint() function that generates a numpy array of a given length filled with random numbers between a given range.

In the second method, we used a relatively new numpy2 module to create the array. It uses random9 that provide an additional state to manage and generate random bits.

In the final method, we discussed how to fill array with random numbers in Python using the list comprehension method and the random0 function. Essentially, we create a loop and run the randint() function the required number of times and add the generated number to a list.

How to fill an array numpy?

fill() method is used to fill the numpy array with a scalar value. If we have to initialize a numpy array with an identical value then we use numpy. ndarray. fill().

How do I fill an empty numpy array?

There are two simple ways to fill NumPy arrays. You can fill an existing array with a specific value using numpy. fill() . Alternatively, you can initialize a new array with a specific value using numpy.

What is array [:] in Python?

Arrays in Python are Data Structures that can hold multiple values of the same type. Often, they are misinterpreted as lists or Numpy Arrays.

How do you fill an empty array with zeros in Python?

zeros() method. In this example, we are creating a NumPy array with zeros as the numpy. zeros() function is used which returns a new array of given shape and type, with zeros.