How to Repeat a String in Python?

Introduction

Python is a versatile programming language for handling string data types and operations. String repetition is a common task in various programming and text manipulation tasks.

Whether you're repeating a string for testing purposes or require formatting texts, Python offers various methods to repeat a string.

This guide covers different approaches to string repetition in Python through practical examples.

Prerequisites

• Python 3 installed and configured (check the Python version before starting).
• An IDE or text editor for Python.
• (Optional) Python modules, such as Itertool functions, NumPy, or Pandas.

Repeat a String via * Operator

The simplest way to repeat a string in Python is with the * operator. Use the operator on a string to repeat the string a provided number of times.

The syntax for the operation is:

result = string * number

The code below demonstrates how to repeat the string "Hello, world!" five times:

result = "Hello, world!" * 5
print(result)

Alternatively, store the string and number in variables and change them as needed. For example:

my_string = "Hello, world!"
number = 5
result = my_string * number
print(result)

In both cases, the result is the string "Hello, world!" repeated five times.

Repeat a String via for Loop

Another built-in way to repeat a string in Python is using a for loop and the range function. Iterate over a provided range and append the string to a variable in each iteration.

The following code demonstrates the procedure to repeat a string five times:

result = ""

for _ in range(5):
  result += "Hello, world!"

print(result)

The code does the following:

• Creates an empty placeholder string variable result.
• Goes through five iterations using the range(5) function.
• Appends the provided string each time to the result variable using the += operator.
• Prints the result to the console.

To repeat a string and print on a new line each time, use the for loop and print the string:

for _ in range(5):
  print("Hello, world!")

The for loop repeats the print task five times and exits.

Repeat a String via itertools.repeat()

The itertools library contains various iteration functionalities for Python. The itertools.repeat() function creates an iterable object that repeats a string for a specified number of iterations. The syntax for the function is:

itertools.repeat(string, number)

The code below demonstrates how to use itertools.repeat() to repeat a string in Python:

import itertools
result = "".join(itertools.repeat("Hello, world!", 5))
print(result)

The code uses the join() method on an empty string to append the string iterable object to an empty string.

Alternatively, use the itertools.repeat() function in a for loop to repeat a string. For example:

import itertools
result = ""

for i in itertools.repeat("Hello, world!", 5):
  result+=i

print(result)

The itertools.repeat() function does not pre-generate the repeated values and is faster compared to the built-in range() function.

Repeat a String via numpy.repeat()

The NumPy library has various numerical functionalities, including object repetition. The numpy.repeat() function repeats a given object in a Python array. The syntax is:

numpy.repeat(string, number)

The operation result is an array with string elements. Join the array elements on an empty string to repeat a string using this method.

The code below shows how to repeat a string via the numpy.repeat() function:

import numpy as np

result_array = np.repeat("Hello, world!", 5)
result = ''.join(result_array)
print(result)

Use the numpy.repeat() function when working with NumPy arrays or with array operations. When you are not working with arrays, use a simpler method to repeat a string.

Repeat a String for a Length With a User-Defined Function

If a code requires repeating different strings until a given string length, the most efficient approach is to create a custom function.

To create a function for repeating strings until a specified length, define the input and output variables. For example:

• <b>input_string</b> and length - The string to be repeated and the length of the repetition are the input values.
• result - The resulting repetition is the output value.

The code below demonstrates how to perform string repetition until a given length:

def repeat_length(input_string, length):

  number = int(length/len(input_string)+1)

  result = input_string * number

  print(result[:length])

repeat_length("Hello", 12)
repeat_length("World", 7)

The repeat_length() function does the following:

• There are two user-input variables, the string (input_string) and the length of the final string (length).
• Line two determines the least number of repetitions necessary to get the correct number of characters.
• In line three, the function repeats the string for the calculated number of times using the * operator.
• Lastly, the function prints the result up to the provided length using string slicing.

Call the function and provide a string and length to test the results.

Conclusion

After reading this guide, you know several ways to repeat a string in Python. As each method provides different benefits, knowing different ways to perform the same task is beneficial.

Next, learn how to use Python substrings to get parts of a string.