Python Program to Find All Non Repeated Characters in a String

In the previous article, we have discussed Program to Find Lexicographic Rank of a Given String

Given a string and the task is to find all the Non repeated characters in a given String.

Counter function in Python:

The counter is a set and dict subset. Counter() takes an iterable entity as an argument and stores the elements as keys and the frequency of the elements as a value. So, in collections, if we transfer a string. When you call Counter(), you’ll get a Counter class object with characters as keys and their frequency in a string as values.

Counter() returns a Counter type object (a subclass of dict) with all characters in the string as keys and their occurrence count as values. We’ll use the [] operator to get the occurrence count of the characters from it.

Examples:

Example1:

Input:

Given String = "hello this is btechgeeks"

Output:

In a Given String,{ hello this is btechgeeks } all Non-repeating Characters are:
o b c g k

Example2:

Input:

Given String = "good morning btechgeeks"

Output:

In a Given String,{ good morning btechgeeks } all Non-repeating Characters are:
d m r i b t c h k s

Program to Find All Non-Repeated Characters in a String in Python

Below are the ways to find all the Non repeated characters in a given String:

Using Counter() Function (Static input)
Using Counter() Function (User input)

Method #1: 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 elements using the Counter() function which returns the element and its frequency as a key-value pair and stores this dictionary in another variable (say strngfreqelements).
Traverse in this frequency dictionary using the for loop.
Inside the loop, check if the Key has the frequency 1 and key not equal to space using the if conditional statement
If the statement is true, then print the value of the key.
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.
gven_str = "hello this is btechgeeks"
# Calculate the frequency of all the given string elements using the Counter() function
# which returns the element and its frequency as a key-value pair and stores this
# dictionary in another variable (say strngfreqelements).
strngfreqelements = Counter(gven_str)
print("In a Given String,{", gven_str, "} all Non-repeating Characters are:")
# Traverse in this frequency dictionary using the for loop.
for key in strngfreqelements:
    # Inside the loop, check if the Key has the frequency 1 and key not equal to space
    # using the if conditional statement
    if(strngfreqelements[key] == 1 and key != " "):
     # If the statement is true, then print the value of the key.
        print(key, end=" ")

Output:

In a Given String,{ hello this is btechgeeks } all Non-repeating Characters are:
o b c g k

Method #2: Using Counter() function (Hashing, User Input)

Approach:

Import the Counter() function from collections using the import keyword.
Give the string as user input using the input() function and store it in a variable.
Calculate the frequency of all the given string elements using the Counter() function which returns the element and its frequency as a key-value pair and stores this dictionary in another variable (say strngfreqelements).
Traverse in this frequency dictionary using the for loop.
Inside the loop, check if the Key has the frequency 1 and key not equal to space using the if conditional statement
If the statement is true, then print the value of the key.
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.
gven_str = input("Enter some random String = ")
# Calculate the frequency of all the given string elements using the Counter() function
# which returns the element and its frequency as a key-value pair and stores this
# dictionary in another variable (say strngfreqelements).
strngfreqelements = Counter(gven_str)
print("In a Given String,{", gven_str, "} all Non-repeating Characters are:")
# Traverse in this frequency dictionary using the for loop.
for key in strngfreqelements:
    # Inside the loop, check if the Key has the frequency 1 and key not equal to space
    # using the if conditional statement
    if(strngfreqelements[key] == 1 and key != " "):
     # If the statement is true, then print the value of the key.
        print(key, end=" ")

Output:

Enter some random String = good morning btechgeeks
In a Given String,{ good morning btechgeeks } all Non-repeating Characters are:
d m r i b t c h k s

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