Python program to omit K length Rows

When working with lists of lists, you may need to filter out rows based on their length. This Python program demonstrates how to omit rows that have exactly K elements using iteration and the len() method.

Example

Below is a demonstration of the same −

my_list = [[41, 7], [8, 10, 12, 8], [10, 11], [6, 82, 10]]

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

my_k = 2
print("The value of K is")
print(my_k)

my_result = []

for row in my_list:
   if len(row) != my_k :
      my_result.append(row)

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

Output

The list is :
[[41, 7], [8, 10, 12, 8], [10, 11], [6, 82, 10]]
The value of K is
2
The resultant list is :
[[8, 10, 12, 8], [6, 82, 10]]

How It Works

• A list of lists is defined and displayed on the console.

• The K value is defined and displayed on the console.

• An empty list is created to store the result.

• The original list is iterated over row by row.

• If the length of the current row is not equal to K, it is appended to the result list.

• The filtered result is displayed on the console.

Using List Comprehension

You can achieve the same result more concisely using list comprehension −

my_list = [[41, 7], [8, 10, 12, 8], [10, 11], [6, 82, 10]]
my_k = 2

# Filter out rows with length K
my_result = [row for row in my_list if len(row) != my_k]

print("Original list:", my_list)
print("K value:", my_k)
print("Filtered list:", my_result)

Original list: [[41, 7], [8, 10, 12, 8], [10, 11], [6, 82, 10]]
K value: 2
Filtered list: [[8, 10, 12, 8], [6, 82, 10]]

Conclusion

Use iteration with len() and append() for readable filtering. List comprehension provides a more concise approach for the same operation.