Python Program to Remove Odd Occurring Characters from the String

In the previous article, we have discussed Python Program for Given Two Numbers a and b Find all x Such that a % x = b

Given a string and the task is to remove all the odd occurring characters from the given string.

Examples:

Example1:

Input:

Given String = "goodmorning"

Output:

The given string { goodmorning } after removing odd frequency elements is : gnng

Example2:

Input:

Given String = "thisisbtechgeeks"

Output:

The given string { thisisbtechgeeks } after removing odd frequency elements is : thiith

Program to Remove Odd Occurring Characters from the String in Python.

Below are the ways to remove all the odd occurring characters from the given string in python:

• Using Dictionary (Hashing, User Input)
• Using Counter() function (Hashing, Static Input)
• Using Counter() function (Hashing, User Input)
• Using Counter() function (Hashing, User Input)

Method #1: Using Dictionary (Hashing, Static Input)

Approach:

• Take a dictionary and initialize it to empty using the {} or dict() say freqncyDictionary.
• Give the string as static input and store it in a variable.
• Loop in the given string using the For loop.
• Inside the For loop, Check if the string character is present in the dictionary or not using the if conditional statement and ‘in’ keyword.
• If the above condition is true then increment the count of the string character in the dictionary by 1.
• Else initialize the dictionary with the string character as key and value as 1.
• Take a string that stores all the characters which are not occurring odd a number of times and initialize it to null string using “or str()
• loop in the given string using the for loop.
• Check if the character has an even frequency by checking the value of that character in the frequency dictionary we check using the if conditional statement.
• If it is true then concatenate this character to modifd_string using string concatenation.
• Print the modifd_string string.
• The Exit of the Program.

Below is the implementation:

# Take a dictionary and initialize it to empty
# using the {} or dict() say freqncyDictionary.
freqncyDictionary = {}
# Give the string as static input and store it in a variable
gvnstrng = "goodmorning"
# Loop in the given string using the For loop.
for i in gvnstrng:
        # Inside the For loop,
    # Check if the string character is present in the dictionary
    # or not using the if conditional statement and 'in' keyword.
    if i in freqncyDictionary.keys():
                # If it is true then increment the count of the string character
        # in the dictionary by 1.
        freqncyDictionary[i] = freqncyDictionary[i]+1
    # Else initialize the dictionary with the string character as key and value as 1.
    else:
        freqncyDictionary[i] = 1
# Take a string which stores all the characters which are not occuring odd number
# of times and initialize it to null string using "" or str()
modifd_string = ""
# loop in the given string using the for loop
for charac in gvnstrng:

        # check if the character has even frequency by checking value of that character in frequency dictionary
        # we check using the if conditional statement
    if(freqncyDictionary[charac] % 2 == 0):
        # if it is true then concatenate this character to modifd_string using string concatenation
        modifd_string = modifd_string+charac


# print the modifd_string string
print('The given string {', gvnstrng,
      '} after removing odd frequency elements is :', modifd_string)

Output:

The given string { goodmorning } after removing odd frequency elements is : gnng

Method #2: Using Dictionary (Hashing, User Input)

Approach:

• Take a dictionary and initialize it to empty using the {} or dict() say freqncyDictionary.
• Give the string as the user input using the input() function and store it in a variable.
• Loop in the given string using the For loop.
• Inside the For loop, Check if the string character is present in the dictionary or not using the if conditional statement and ‘in’ keyword.
• If the above condition is true then increment the count of the string character in the dictionary by 1.
• Else initialize the dictionary with the string character as key and value as 1.
• Take a string that stores all the characters which are not occurring odd a number of times and initialize it to null string using “or str()
• loop in the given string using the for loop.
• Check if the character has an even frequency by checking the value of that character in the frequency dictionary we check using the if conditional statement.
• If it is true then concatenate this character to modifd_string using string concatenation.
• Print the modifd_string string.
• The Exit of the Program.

Below is the implementation:

# Take a dictionary and initialize it to empty
# using the {} or dict() say freqncyDictionary.
freqncyDictionary = {}
# Give the string as the user input using the input() function and store it in a variable.
gvnstrng = input("Enter some random string = ")
# Loop in the given string using the For loop.
for i in gvnstrng:
        # Inside the For loop,
    # Check if the string character is present in the dictionary
    # or not using the if conditional statement and 'in' keyword.
    if i in freqncyDictionary.keys():
                # If it is true then increment the count of the string character
        # in the dictionary by 1.
        freqncyDictionary[i] = freqncyDictionary[i]+1
    # Else initialize the dictionary with the string character as key and value as 1.
    else:
        freqncyDictionary[i] = 1
# Take a string which stores all the characters which are not occuring odd number
# of times and initialize it to null string using "" or str()
modifd_string = ""
# loop in the given string using the for loop
for charac in gvnstrng:

        # check if the character has even frequency by checking value of that character in frequency dictionary
        # we check using the if conditional statement
    if(freqncyDictionary[charac] % 2 == 0):
        # if it is true then concatenate this character to modifd_string using string concatenation
        modifd_string = modifd_string+charac


# print the modifd_string string
print('The given string {', gvnstrng,
      '} after removing odd frequency elements is :', modifd_string)

Output:

Enter some random string = thisisbtechgeeks
The given string { thisisbtechgeeks } after removing odd frequency elements is : thiith

Method #3: Using Counter() function (Hashing, Static Input)

Approach:

• Import the Counter() function from collections using the import keyword.
• Give the string as static input and store it in a variable
• Calculate the frequency of all the given string characters using the Counter() function which returns the element and its frequency as key-value pair  and store this dictionary in a variable(say freqncyDictionary)
• Take a string that stores all the characters which are not occurring odd a number of times and initialize it to null string using “or str()
• loop in the given string using the for loop.
• Check if the character has an even frequency by checking the value of that character in the frequency dictionary we check using the if conditional statement.
• If the above condition is true then concatenate this character to modifd_string using string concatenation.
• Print the modifd_string string.
• The Exit of the Program.

Below is the implementation:

# Import the Counter() function from collections using the import keyword.
from collections import Counter
# Give the string as static input and store it in a variable
gvnstrng = "goodmorning"
# Calculate the frequency of all the given string characters using the Counter()
# function which returns the element and its frequency as key-value pair
# and store this dictionary in a variable(say freqncyDictionary)
freqncyDictionary = Counter(gvnstrng)
# Take a string which stores all the characters which are not occuring odd number
# of times and initialize it to null string using "" or str()
modifd_string = ""
# loop in the given string using the for loop
for charac in gvnstrng:

        # check if the character has even frequency by checking value of that character in frequency dictionary
        # we check using the if conditional statement
    if(freqncyDictionary[charac] % 2 == 0):
        # if it is true then concatenate this character to modifd_string using string concatenation
        modifd_string = modifd_string+charac


# print the modifd_string string
print('The given string {', gvnstrng,
      '} after removing odd frequency elements is :', modifd_string)

Output:

The given string { goodmorning } after removing odd frequency elements is : gnng

Method #4: Using Counter() function (Hashing, User Input)

Approach:

• Import the Counter() function from collections using the import keyword.
• Give the string as the user input using the input() function and store it in a variable.
• Calculate the frequency of all the given string characters using the Counter() function which returns the element and its frequency as key-value pair  and store this dictionary in a variable(say freqncyDictionary)
• Take a string that stores all the characters which are not occurring odd a number of times and initialize it to null string using “or str()
• loop in the given string using the for loop.
• Check if the character has an even frequency by checking the value of that character in the frequency dictionary we check using the if conditional statement.
• If the above condition is true then concatenate this character to modifd_string using string concatenation.
• Print the modifd_string string.
• The Exit of the Program.

Below is the implementation:

# Import the Counter() function from collections using the import keyword.
from collections import Counter
# Give the string as user input using the input() function and store it in a variable
gvnstrng = input("Enter some random string = ")
# Calculate the frequency of all the given string characters using the Counter()
# function which returns the element and its frequency as key-value pair
# and store this dictionary in a variable(say freqncyDictionary)
freqncyDictionary = Counter(gvnstrng)
# Take a string which stores all the characters which are not occuring odd number
# of times and initialize it to null string using "" or str()
modifd_string = ""
# loop in the given string using the for loop
for charac in gvnstrng:

        # check if the character has even frequency by checking value of that character in frequency dictionary
        # we check using the if conditional statement
    if(freqncyDictionary[charac] % 2 == 0):
        # if it is true then concatenate this character to modifd_string using string concatenation
        modifd_string = modifd_string+charac


# print the modifd_string string
print('The given string {', gvnstrng,
      '} after removing odd frequency elements is :', modifd_string)

Output:

Enter some random string = thisisbtechgeeks
The given string { thisisbtechgeeks } after removing odd frequency elements is : thiith

Remediate your knowledge gap by attempting the Python Code Examples regularly and understand the areas of need and work on them.

• Python Program to Find the Least Frequent Character in a String
• Python Program to Check whether String Contains Unique Characters
• Program to Find All Non Repeated Characters in a String
• Python Program to Find the Sum of all Odd Frequency Elements in an Array/List