Python: Remove all consecutive duplicates of a given string

Last update on April 19 2025 13:05:11 (UTC/GMT +8 hours)

Remove consecutive duplicates in string.

Write a Python program to remove all consecutive duplicates of a given string.

Visual Presentation:

Sample Solution - 1:

Python Code:

# Import groupby from itertools
from itertools import groupby 

# Function to remove consecutive duplicates
def remove_all_consecutive(str1):
  
  # Initialize empty result string
  result_str = []

  # Group string into consecutive characters
  for (key,group) in groupby(str1):
    
    # Append only one instance of each character
    result_str.append(key)

  # Join characters into string  
  return ''.join(result_str)

# Test string
str1 = 'xxxxxyyyyy'

# Print original string
print("Original string:" + str1)

# Print string to modify 
print("After removing consecutive duplicates:")

# Print modified string
print(remove_all_consecutive(str1)) 

Sample Output:

Original string:xxxxxyyyyy
After removing consecutive duplicates: xxxxxyyyyy
xy

Flowchart:

Visual Presentation:

Sample Solution - 2:

Python Code:

# Import itertools
import itertools

# Function to remove consecutive duplicates
def remove_consecutive_duplicates(s1):

  # Group into consecutive characters 
  # Keep only first instance of each
  return ''.join(i for i, _ in itertools.groupby(s1))

# Test string  
s1= "aabcdaee"

# Print original string
print("Original String: ",s1)  

# Print message
print("\nRemoving all consecutive duplicates:")

# Print string with duplicates removed
print(remove_consecutive_duplicates(s1)) 

Sample Output:

Original String:  aabcdaee

Removing all consecutive duplicates:
abcdae

Flowchart:

For more Practice: Solve these Related Problems:

• Write a Python program to remove all consecutive duplicate characters from a string using iteration.
• Write a Python program to use recursion to eliminate consecutive repeated characters from an input string.
• Write a Python program to implement a function that returns a string with no consecutive duplicates by comparing each character to its predecessor.
• Write a Python program to apply regular expressions to collapse repeated characters into a single instance.

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