Python program to repeat M characters of a string N times

In this article, the task is to write a Python program to repeat M characters of string N times.

Method 1:

1. Define a function that will take a word, m, and n values as arguments.
2. If M is greater than the length of the word. Set m value equal to the length of the word
3. Now store the characters needed to be repeated into a string named repeat_string using slicing.
4. Initialize an empty string named as a result
5. Concatenate the repeat_string to result for n times.
6. Now print the string.

Below is the implementation:

Python3

def repeat(word, m, n):

    # if number of characters greater than length of word.
    # set number of characters = length of word
    if(m > len(word)):
        m = len(word)

    repeat_word = word[:m]
    result = ""

    for i in range(n):
        result = result+repeat_word
    print(result)


# driver code
repeat("geeks", 2, 3)

Output:

gegege

Time Complexity : O(n)
Auxiliary Space : O(n)

Method 2:

1. Define a function that will take a word, m, n values as arguments.
2. if M is greater than length of word. set m value equal to the length of word.
3. Now store the characters needed to be repeated into a string named repeat_string using slicing.
4. Multiply the repeat_string with n.
5. Now print the string.

Python3

def repeat(word, m, n):

    # if number of characters greater than length of word.
    # set number of characters = length of word
    if(m > len(word)):
        m = len(word)

    repeat_word = word[:m]
    print(repeat_word*n)

# driver code
repeat("geeks", 2, 3)

Output:

gegege

The time and space complexity for both methods are the same:

Time Complexity : O(n)
Auxiliary Space : O(n)

Method 3: Using itertools

Here’s another method that can be used to repeat M characters of a string N times using the itertools module in Python:

Python3

import itertools

def repeat(word, m, n):
    if m > len(word):
        m = len(word)

    repeat_word = word[:m]
    result = "".join(itertools.islice(itertools.repeat(repeat_word), n))
    print(result)

# driver code
repeat("geeks", 2, 3)

Output

gegege

Time Complexity : O(n)
Auxiliary Space : O(n)

Method 4: Using operator.mul()+slicing

Approach

1. Define a function that will take a word, m, n values as arguments.
2. if M is greater than length of word. set m value equal to length of word.
3. Now store the characters needed to be repeated into a string named repeat_string using slicing.
4. Multiply the repeat_string with n.(using operator.mul())
5. Now print the string.

Python3

def repeat(word, m, n):

    # if number of characters greater than length of word.
    # set number of characters = length of word
    if(m > len(word)):
        m = len(word)

    repeat_word = word[:m]
    import operator
    print(operator.mul(repeat_word,n))

# driver code
repeat("geeks", 2, 3)

Output

gegege

The time and space complexity for both methods is the same:

Time Complexity : O(n)
Auxiliary Space : O(n)