Convert number to list of integers in Python

Converting a number to a list of its individual digits is a common task in Python programming. This article explores two efficient approaches: list comprehension and the map() function with str().

Using List Comprehension

List comprehension provides a concise way to convert each digit by first converting the number to a string, then iterating through each character and converting it back to an integer ?

Example

number = 1342

# Given number
print("Given number:", number)

# Convert to list of digits using list comprehension
digits_list = [int(digit) for digit in str(number)]

# Result
print("List of digits:", digits_list)

The output of the above code is ?

Given number: 1342
List of digits: [1, 3, 4, 2]

Using map() and str()

The map() function applies the int() function to each character in the string representation of the number, creating an efficient solution ?

Example

number = 1342

# Given number
print("Given number:", number)

# Convert to list of digits using map()
digits_list = list(map(int, str(number)))

# Result
print("List of digits:", digits_list)

The output of the above code is ?

Given number: 1342
List of digits: [1, 3, 4, 2]

Handling Negative Numbers

Both methods work with negative numbers, but they include the minus sign. Here's how to handle negative numbers ?

negative_number = -1342

# Method 1: Using absolute value
digits_list1 = [int(digit) for digit in str(abs(negative_number))]
print("Using abs():", digits_list1)

# Method 2: Remove minus sign first
digits_list2 = [int(digit) for digit in str(negative_number) if digit != '-']
print("Filtering minus:", digits_list2)

Using abs(): [1, 3, 4, 2]
Filtering minus: [1, 3, 4, 2]

Comparison

Conclusion

Both list comprehension and map() effectively convert numbers to digit lists. Choose list comprehension for readability or map() for slightly better performance with large numbers.