Skip to main content

Count occurrences of a character in string in Python

Hello everyone! Today we are going to see how can we count the occurrences of a character in a given string using Python.

Python provides a library method count which can be used to count the occurrence of a substring in a given string. Below code snippet takes a character as a substring and returns the count of that in the source string.
# Enter the string in which we need to search 
sentence = input("Enter a string\n")
 
# Enter a string/character which needs to be searched
sub_string = input("Enter the substring to search\n")
 
# Getting the count of the sub string in source string - convert both to lowercase if we want to count irrespective of case
count_of_substring = sentence.lower().count(sub_string.lower())
 
# Print the count of the substring in the source string
print('Count of ' + sub_string + ' in ' + sentence + ' is ' + str(count_of_substring))
The output of this program will be as follows -
>> Enter a string
Help is always given at Hogwarts to those who ask for it
>> Enter the substring to search
h
>> Count of h in Help is always given at Hogwarts to those who ask for it is 4
If you do not wish to use the library method and want to implement your own then you can do this as follows -
def character_count(source_string, character):
 
    # Converting source string and character to lower case to make them case insensitive    
    source_string = source_string.lower()
    character = character.lower()
    
    # Variable to hold the count of character
    count_of_character = 0    
    
    # Iterating through the possible values of i, where i is the starting index of each substring which is of the same length as the substring entered.    
    for i in range(len(source_string) - len(character) + 1):
       
        # Checking if each possible substring of the correct length is equivalent to the substring entered. If so, I increment my count by 1.
     if source_string[i: i + len(character)] == character:
            count_of_character += 1    
 
    return count_of_character
 
 
# Enter the string in which we need to search
sentence = input("Enter a string\n")
 
# Enter a string/character which needs to be searchedsub_string = input("Enter the substring to search\n")
 
# Print the count
print('Count of ' + sub_string + ' in ' + sentence + ' is ' + str(character_count(sentence, sub_string)))
The output of this program will be -
>> Enter a string
Help is always given at Hogwarts to those who ask for it
>> Enter the substring to search
h
>> Count of h in Help is always given at Hogwarts to those who ask for it is 4

Conclusion

In this post, we discussed how to calculate the number of occurrences of a character in a given string.

I would love to hear your thoughts on this post and would like to have suggestions from you to make this post better. 

Feel free to befriend me on Facebook, Twitter or Linked In or say Hi by email.

Comments

Post a Comment

Popular posts from this blog

Parsing XML using Retrofit

Developing our own type-safe HTTP library to interface with a REST API can be a real pain as we have to handle many aspects - making connections caching retrying failed requests threading response parsing error handling, and more.  Retrofit, on the other hand, is a well-planned, documented and tested library that will save you a lot of precious time and headaches. In this tutorial, we are going to discuss how we can parse the XML response returned from  https://timesofindia.indiatimes.com/rssfeedstopstories.cms  using the Retrofit library. To work with Retrofit, we need three classes -  Model class to map the JSON data Interfaces which defines the possible HTTP operations Retrofit.Builder class - Instance which uses the interface and the Builder API which allows defining the URL endpoint for the HTTP operation. Every method of the above interface represents on possible API call. The request type is specified by using appropriate annotations (GET, POST). The respon

Threads in Java - CountDownLatch (Part 12)

A CountDownLatch is a synchronizer which allows one thread to wait for one or more threads before starts processing. A good application of  CountDownLatch is in Java server-side applications where a thread cannot start execution before all the required services are started. Working A  CountDownLatch is initialized with a given count which is the number of threads it should wait for. This count is decremented by calling countDown() method by the threads once they are finished execution. As soon as the count reaches to zero, the waiting task starts running. Code Example Let us say we require three services, LoginService, DatabaseService and CloudService to be started and ready before the application can start handling requests. Output Cloud Service is up! Login Service is up! Database Service is up! All services are up. Now the waiting thread can start execution. Here, we can see that the main thread is waiting for all the three services to start before starting its own

Threads in Java - yield(), sleep() and join() (Part 4)

Let's say we want to stop the execution of a thread. How do we do this? There are three methods in the Thread class which can be used to stop the execution of a thread. Let us discuss these methods one by one 1. Yield method Suppose there are two threads A and B. A takes 10 minutes to complete a job while B takes only 10 seconds. At first, A and B both are in the RUNNABLE state then Thread Scheduler gives resources to A to run. Now B has to wait for 10 minutes to do a 10 seconds job. This very inefficient. Wouldn't it be great if we have some way to prevent the execution of A in between so that B can run? Fortunately, yield() method helps us in achieving this.  If a thread calls yield() method, it suggests the Thread Scheduler that it is ready to pause its execution. But it depends upon the Thread Scheduler to consider this suggestion. It can entirely ignore it. If a thread calls yield() method, the Thread Scheduler checks if there is any thread with same/high