Python: Find the characters which occur in more than and less than a given number in list of strings

Last update on July 05 2025 07:25:02 (UTC/GMT +8 hours)

25. Find characters in strings occurring more or less than a number

Write a Python program to find the characters in a list of strings that occur more or less than a given number.

Sample Solution:

Python Code:

# Import the Counter class from the collections module
from collections import Counter 

# Import the chain function from the itertools module
from itertools import chain 

# Define a function 'max_aggregate' that finds characters occurring more or less than 'N' times in a list of strings
def max_aggregate(list_str, N):
    # Create a generator 'temp' that converts each string into a set of unique characters
    temp = (set(sub) for sub in list_str) 
    
    # Count the occurrences of characters across all sets using Counter and chain them together
    counts = Counter(chain.from_iterable(temp)) 
    
    # Create a list 'gt_N' containing characters occurring more than 'N' times
    gt_N = [chr for chr, count in counts.items() if count > N]
    
    # Create a list 'lt_N' containing characters occurring less than 'N' times
    lt_N = [chr for chr, count in counts.items() if count < N]
    
    # Return the characters occurring more and less than 'N' times
    return gt_N, lt_N

# Create a list of strings 'list_str'
list_str = ['abcd', 'iabhef', 'dsalsdf', 'sdfsas', 'jlkdfgd'] 

# Print a message to indicate the display of the original list
print("Original list:")

# Print the content of 'list_str'
print(list_str)

# Define an integer 'N'
N = 3

# Call the 'max_aggregate' function with 'list_str' and 'N' and store the result in 'result'
result = max_aggregate(list_str, N)

# Print a message to indicate the display of characters occurring more than 'N' times
print("\nCharacters of the said list of strings which occur more than:", N)

# Print the characters from 'result[0]'
print(result[0])

# Print a message to indicate the display of characters occurring less than 'N' times
print("\nCharacters of the said list of strings which occur less than:", N)

# Print the characters from 'result[1]'
print(result[1]) 

Sample Output:

Original list:
['abcd', 'iabhef', 'dsalsdf', 'sdfsas', 'jlkdfgd']

Characters of the said list of strings which occur more than: 3
['a', 'd', 'f']

Characters of the said list of strings which occur less than: 3
['c', 'b', 'h', 'e', 'i', 's', 'l', 'k', 'j', 'g']

Flowchart:

For more Practice: Solve these Related Problems:

• Write a Python program to combine multiple strings into one and count each character's frequency using collections.Counter, then filter by a threshold.
• Write a Python program to iterate over a list of strings and output two lists: one for characters that occur more than a specified count and one for those that occur less.
• Write a Python program to implement a function that takes a list of strings and two thresholds, returning characters meeting each condition.
• Write a Python program to use set operations and Counter to determine which characters occur more or less than a given number across multiple strings.

Go to:

• Python Data Types Collections Exercises Home ↩
• Python Exercises Home ↩

Previous: Write a Python program to calculate the maximum aggregate from the list of tuples (pairs).
Next: Write a Python program to find the difference between two list including duplicate elements. Use collections module.

Python Code Editor: