Python itertools.repeat() Function

The Python itertools.repeat() function is used to create an iterator that returns the same value repeatedly. This function is commonly used when a constant value needs to be provided multiple times in an iteration.

By default, it repeats the value indefinitely unless a repetition limit is specified.

Syntax

Following is the syntax of the Python itertools.repeat() function −

itertools.repeat(object, times=None)

Parameters

This function accepts the following parameters −

• object: The value to be repeated.
• times (optional): The number of times the value should be repeated. If not specified, the repetition is infinite.

Return Value

This function returns an iterator that yields the specified value repeatedly.

Example 1

Following is an example of the Python itertools.repeat() function. Here, we repeat the string "hello" five times −

import itertools

repeater = itertools.repeat("hello", 5)
for word in repeater:
   print(word)

Following is the output of the above code −

hello
hello
hello
hello
hello

Example 2

Here, we use itertools.repeat() to generate a constant value indefinitely and limit it using itertools.islice() function −

import itertools

constant_value = itertools.repeat(10)
limited_values = itertools.islice(constant_value, 6)
for num in limited_values:
   print(num)

Output of the above code is as follows −

10
10
10
10
10
10

Example 3

Now, we use itertools.repeat() function with the map() function to apply a function multiple times −

import itertools

def power(x, y):
   return x ** y

bases = [2, 3, 4, 5]
exponents = itertools.repeat(3)
results = map(power, bases, exponents)
for result in results:
   print(result)

The result obtained is as shown below −

8
27
64
125

Example 4

If you use the itertools.repeat() function without a specified repetition limit, it will run indefinitely. To prevent infinite loops, you can use conditions or the islice() function from itertools.

Here, we repeat a tuple value but limit it using itertools.islice() function −

import itertools

value = (1, 2, 3)
repeated_values = itertools.repeat(value)
limited_repeated = itertools.islice(repeated_values, 4)
for val in limited_repeated:
   print(val)

The result produced is as follows −

(1, 2, 3)
(1, 2, 3)
(1, 2, 3)
(1, 2, 3)