Python – Reform K digit elements

When working with lists of numbers, you may need to reform K digit elements by concatenating all numbers into a string and then splitting them into chunks of K digits. This technique uses string manipulation and list comprehension.

Example

Below is a demonstration of reforming elements into 3-digit chunks ?

my_list = [231, 67, 232, 1, 238, 31, 793]

print("The list is :")
print(my_list)

K = 3
print("The value of K is")
print(K)

# Join all numbers as a single string
temp = ''.join([str(ele) for ele in my_list])
print("Combined string:", temp)

my_result = []

# Split into K-digit chunks
for index in range(0, len(temp), K):
   chunk = temp[index: index + K]
   if chunk:  # Only add non-empty chunks
       my_result.append(int(chunk))

print("The resultant list is :")
print(my_result)

The list is :
[231, 67, 232, 1, 238, 31, 793]
The value of K is
3
Combined string: 2316723212383179
The resultant list is :
[231, 672, 321, 238, 317, 9]

How It Works

The algorithm follows these steps:

1. Concatenation: All list elements are converted to strings and joined together
2. Chunking: The combined string is split into K-digit segments
3. Conversion: Each chunk is converted back to integer and added to result

Alternative Using List Comprehension

Here's a more concise approach using list comprehension ?

my_list = [231, 67, 232, 1, 238, 31, 793]
K = 3

# One-liner approach
temp = ''.join([str(ele) for ele in my_list])
result = [int(temp[i:i+K]) for i in range(0, len(temp), K) if temp[i:i+K]]

print("Original list:", my_list)
print("Reformed list:", result)

Original list: [231, 67, 232, 1, 238, 31, 793]
Reformed list: [231, 672, 321, 238, 317, 9]

Conclusion

Reforming K digit elements involves concatenating all numbers into a string and splitting into fixed-size chunks. This technique is useful for data restructuring and number manipulation tasks.