Split a List having Single Integer - Python

We are given a list containing a single integer, and our task is to split it into separate digits while keeping the list structure intact. For example, if the input is a = [12345], the output should be [1, 2, 3, 4, 5]. Let's discuss different methods to do this in Python.

Using List Comprehension

We can convert the integer to a string, iterate through its characters and convert them back to integers.

# Initializing list  
a = [12345]  

# Splitting the integer into digits  
result = [int(digit) for digit in str(a[0])]  

print(result)

[1, 2, 3, 4, 5]

Explanation:

• str(a[0]) converts the integer to a string "12345".
• The list comprehension iterates through each character, converting it back to an integer.

Let's explore some more ways and see how we can split a list having single integer in Python.

Using map()

map() function can apply int() to each character of the string representation of the number.

# Initializing list  
a = [12345]  

# Splitting the integer using map()  
result = list(map(int, str(a[0])))  

print(result)

[1, 2, 3, 4, 5]

Explanation:

• str(a[0]) converts the integer to a string.
• map(int, str(a[0])) applies int() to each digit.
• list() converts the result back to a list.

Using for Loop and Integer Division

We can extract digits manually by repeatedly dividing the number by 10.

# Initializing list  
a = [12345]  

# Extracting digits using integer division  
num = a[0]  
result = []  

while num > 0:  
    result.append(num % 10)  # Extract last digit  
    num //= 10  # Remove last digit  

result.reverse()  # Reverse to maintain correct order  

print(result)

[1, 2, 3, 4, 5]

Explanation:

• The loop extracts digits from right to left using num % 10.
• num //= 10 removes the last digit after extracting it.
• Since digits are added in reverse order, result.reverse() ensures the correct order.
• This method does not use string conversion but is slightly slower than string-based methods.

Using divmod() for Better Integer Division

divmod() function simplifies integer division and remainder extraction.

# Initializing list  
a = [12345]  

# Extracting digits using divmod()  
num = a[0]  
result = []  

while num > 0:  
    num, digit = divmod(num, 10)  # Get quotient and last digit  
    result.append(digit)  

result.reverse()  

print(result)

[1, 2, 3, 4, 5]

Explanation:

• divmod(num, 10) returns both the quotient and last digit in one step.
• This avoids separate division and modulo operations, making the method more efficient than a standard loop.