Print first m multiples of n without using any loop in Python

While loops are the traditional way to print first m multiples of n, Python provides other efficient methods to perform this task without explicitly using loops. This article will explore different approaches to Printing first m multiples of n without using any loop in Python.

Using List Comprehension

List comprehension provides a compact way to generate lists. Here, it can be used to calculate the multiples of n by iterating over a range of numbers.

n = 5  
m = 10  

# Loop through numbers from 1 to 'm'
#(inclusive) and multiply each by 'n'
multiples = [n * i for i in range(1, m + 1)]
print(multiples)

[5, 10, 15, 20, 25, 30, 35, 40, 45, 50]

Explanation:

• range(1, m + 1) generates numbers from 1 to mmm, inclusive.
• For each number in the range, it computes n×i.
• The result is stored in a list multiples.

Let's explore some more methods to print first m multiples of n without using any loop in Python.

Using map()

map() function applies a given function to each item of an iterable. It can be used to compute multiples of n for the required range.

n = 5
m = 10

# Use the map with lambda calculate the multiples of 'n'
# range function generates
# numbers from 1 to 'm' (inclusive)
multiples = list(map(lambda x: n * x, range(1, m + 1)))

print(multiples)

[5, 10, 15, 20, 25, 30, 35, 40, 45, 50]

Explanation:

• range(1, m + 1) generates numbers from 1 to m.
• The lambda function multiplies each number in the range by n.
• map() applies the lambda function to each element and the results are converted to a list using list().

Using NumPy

NumPy library is a powerful tool for numerical operations in Python. Its array manipulation capabilities make it an efficient choice for generating multiples.

import numpy as np

n = 5
m = 10

# Use NumPy's arange function to create an array of multiples
# Start at 'n', end at 'n * m + 1' (exclusive)
multiples = list(np.arange(n, n * m + 1, n))

print(multiples)

[5, 10, 15, 20, 25, 30, 35, 40, 45, 50]

Explanation:

• np.arange(start, stop, step) generates values from n to n×m with a step of n.
• The result is converted into a list using list().

Using * (Unpacking Operator)

unpacking operator can be used creatively to print the multiples without explicitly storing them in a list.

n = 5
m = 10

#Use a list comprehension to 
#generate the multiples of 'n'
#'*' unpacks the list, printing 
#its elements separated by spaces
print(*[n * i for i in range(1, m + 1)])

5 10 15 20 25 30 35 40 45 50

Explanation:

• [n * i for i in range(1, m + 1)] generates a list of multiples.
• * operator unpacks the list and prints its elements separated by spaces.

Using Recursion

Recursion is another way to compute and print multiples without using loops. It involves repeatedly calling a function until a base condition is met.

def print_multiples(n, m, current=1):
    if current > m:
        return
    print(n * current, end=' ')
    print_multiples(n, m, current + 1)

n = 5
m = 10
print_multiples(n, m)

5 10 15 20 25 30 35 40 45 50 

Explanation:

• The function print_multiples takes three arguments: the number n, the total multiples m and the current multiplier (defaulted to 1).
• Base Condition: Stops when current > m.
• Recursive Call: Prints n×current and calls itself with current + 1.