Python: Find all the common characters in lexicographical order from two given lower case strings

Last update on June 12 2025 12:42:50 (UTC/GMT +8 hours)

Common characters between two strings.

Write a Python program to find all the common characters in lexicographical order from two given lower case strings. If there are no similar letters print "No common characters".

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Sample Solution:

Python Code:

# Import Counter for counting characters
from collections import Counter  

def common_chars(str1,str2):

  # Create Counter objects for each string
  d1 = Counter(str1)  
  d2 = Counter(str2)
  
  # Intersection of the counters gives common elements
  common_dict = d1 & d2

  # If no common elements, return message 
  if len(common_dict) == 0:
    return "No common characters."

  # Get list of common characters
  common_chars = list(common_dict.elements())
  
  # Sort common characters
  common_chars = sorted(common_chars)

  # Join the characters into a string
  return ''.join(common_chars)

# Test strings
str1 = 'Python'
str2 = 'PHP'

# Print test strings 
print("Two strings: "+str1+' : '+str2)

# Print common characters
print(common_chars(str1, str2))

# Test with different strings
str1 = 'Java'
str2 = 'PHP'

# Print test strings
print("Two strings: "+str1+' : '+str2) 

# Print common characters
print(common_chars(str1, str2)) 

Sample Output:

Two strings: Python : PHP
P
Two strings: Java : PHP
No common characters.

Flowchart:

For more Practice: Solve these Related Problems:

• Write a Python program to find the intersection of characters in two lower case strings and return them in lexicographical order.
• Write a Python program to use set operations to find and print common characters between two strings, or "No common characters" if none exist.
• Write a Python program to iterate over two strings and collect characters present in both, then sort the result alphabetically.
• Write a Python program to implement a function that returns the common characters between two strings, ensuring uniqueness and sorted order.

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