Number to list of digits python

1. Use List Comprehension to Split an Integer Into Digits in Python
2. Use the math.ceil() and math.log() Functions to Split an Integer Into Digits in Python
3. Use the map() and str.split() Functions to Split an Integer Into Digits in Python
4. Use a for Loop to Split an Integer Into Digits in Python

This tutorial will discuss different methods to split an integer into digits in Python.

Use List Comprehension to Split an Integer Into Digits in Python

List comprehension is a much shorter and graceful way to create lists that are to be formed based on given values of an already existing list.

In this method, str() and int() functions are also used along with List comprehension to split the integer into digits. str() and int() functions are used to convert a number to a string and then to an integer respectively.

The following code uses list comprehension to split an integer into digits in Python.

num = 13579
x = [int(a) for a in str(num)]
print(x)

Output:

[1, 3, 5, 7, 9]

The number num is first converted into a string using str() in the above code. Then, list comprehension is used, which breaks the string into discrete digits. Finally, the digits are converted back to an integer using the int() function.

Use the math.ceil() and math.log() Functions to Split an Integer Into Digits in Python

The operation of splitting the integer into digits in Python can be performed without converting the number to string first. Moreover, this method is about twice as fast as converting it to a string first.

The math.ceil() function rounds off a number up to an integer. The math.log() function provides the natural logarithm of a number. To use both these functions, we should import the math library.

The math module can be defined as an always accessible and standard module in Python. It provides access to the fundamental C library functions.

The following code uses list comprehension, math.ceil() and math.log() functions to split an integer into digits in Python.

import math
n = 13579
x = [(n//(10**i))%10 for i in range(math.ceil(math.log(n, 10))-1, -1, -1)]
print(x)

Output:

[1, 3, 5, 7, 9]

Use the map() and str.split() Functions to Split an Integer Into Digits in Python

The map() function implements a stated function for every item in an iterable. The item is then consigned as a parameter to the function.

The split() method, as the name suggests, is used to split a string into a list. It has a basic syntax and holds two parameters, separator, and the maxsplit.

The number needs to be already in the string format so that this method could be used.

The following code uses the map() and str.split() functions to split an integer into digits in Python.

str1 = "1 3 5 7 9"
list1 = str1.split()
map_object = map(int, list1)

listofint = list(map_object)
print(listofint)

Output:

[1, 3, 5, 7, 9]

Here, we used the str.split() method to split the given number in string format into a list of strings containing every number. Then the map() function is used, which is utilized to generate a map object which converts each string into an integer. Finally, list(mapping) is used to create a list from the map object.

Use a for Loop to Split an Integer Into Digits in Python

In this method, we use a loop and perform the slicing technique till the specified number of digits (A=1 in this case) and then finally, use the int() function for conversion into an integer.

The following code uses the int()+loop+slice to split an integer into digits in Python.

str1 = '13579'
# initializing substring
A = 1
# create a result list
result = []
for i in range(0, len(str1), A):
    # convert to int, after the slicing process
    result.append(int(str1[i : i + A]))
  
print("The resultant list : " + str(result))

Output:

The resultant list : [1, 3, 5, 7, 9]

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