Python string comparison: Step by step to compare strings in Python

Strings in Python are the collection of sequences of characters. They are stored in the memory as objects. When working with Strings in Python, you might need to compare them to each other. For instance, when users need to reset their password, they need to enter their email address. Then, you need to compare that address with that you have stored in the database. As that said, in this guideline, we will deliver you a comprehensive guide of Python string comparison.

Python String is and is Not Equal to

As mentioned above, strings are the sequence of characters, numbers, letters and even white space. Therefore, it allows coders to interact with text – based data in their programs. 

When it comes to Python string comparison, you need to check if the string is or is not equal to another string. To do this, you’ll want to use == and !== string comparison operators

If the two values are the same, the == operator will return True. On the other hand, in case two values don’t match, the operator returns False. 

The !== operator is contrast to the == operator. It will return False if the two values match and True if they don’t.

You should keep in mind that string comparisons are case sensitive. As a result, lowercase and uppercase letters can affect the results of your comparison

Python String is and is not equal to example

Now, to better understand Python string comparison, let’s consider this example. Imagine you want to build an app game, and players need to answer a question correctly to gain one point. For example, players are asked what is the capital of California, then they need to enter Sacramento to gain one point. Here’s the code of the program

Python string comparison

Let’s break down this code. First, we declare our random state that is Delaware. After that, we use the input () method to deliver the question “ What is the capital of Delaware”  to players. Then, the program declares the correct answer is Dover, and uses an if statement to check if the player’s answer is correct or not. 

Python string comparison

If players answer the question accurately, the if statement is equal to True, and the program prints the message “ You are correct” to the console.

On the other hand, if players enter wrong answer, the code will be as follow

Python string comparison

In this example, we entered Denver instead of Dover. Thus, the if statement is equal to False, and the else statement will be executed.

Python is Operator

Another method of Python string comparison is “is” and “ is not” method. With this method, you can compare if two objects instances are the same based on their objects IDs. This is different from the == method, which compares two variables based on their actual value. As that said, you should use == method when comparing immutable data like strings and numbers. Besides, when you need to compare objects, is method will be more suitable

Let’s consider the following example. Suppose the scores of two users are stored as string. Now, we want to compare these scores to see if they are the same or not. Then, we can use the following code

The code returns

Now, we will break down that code. In this example, you can use the == operator as well. Nevertheless, we choose to use the is method since it uses up less memory and we only need to compare two objects

Let’s look at the if statement. The statement player_one_score is player_two_score is equal to True in this program. Why? Because two variables player_one_score and player_two_score have the same object IDs. If you want to check these IDs, you can use the id keyword

The code returns

Python other comparison operators

Suppose you need to compare strings in lexicographic order. Then, you can use the comparison operators that Python offers to you. Here are they

  • < – less than
  • > – greater than
  • <= – less than or equal to 
  • >= – greater than or equal to

The order will depend on the order of the characters in the alphabet that it is used in your machine while running Python code. Moreover, the order is case – sensitive. As a result, uppercase and lowercase letters can affect your order. For example, “ Cat” will come before “ cat”. To understand this method further, let’s consider the following example

You are about to make a program to take in two students’ names. Then, it will return a message with whose name comes first in the alphabet. Thus, the code will be as follow

student_one = “Penny”

student_two = “Paul”

if student_one > student_two:

print(“Penny comes before Paul in the alphabet.”)

elif student_one < student_two:

print(“Paul comes before Penny in the alphabet.”)

In the first two lines, we declare two variables that store the students’ names: Penny and Paul

After that, use the greater than operator to check if Penny’s name comes before Paul’s name in lexicographic order. In case the if statement is equal to True, the message printed to the console will tell us that Penny comes before Paul in the alphabet

Our code returns

Paul comes before Penny in the alphabet.

Suppose you use elif statement which uses less than operator in this example. Then, if it evaluates to True, a message will be printed to the console telling the user that Paul comes before Penny in the alphabet

Case – Insensitive Comparison

Moving to another Python string comparison – Case – Insensitive Comparison. This method allows you to compare case – insensitive using special string methods like upper () or lower (). In particular, upper () turns the entire strings into uppercase letters. On the other hand, lower () turns them into lowercase letters.

Here’s the example of Case – Insensitive comparison

The code returns

In conclusion

We hope to deliver you some basic knowledge about Python string comparison. However, working with Python is not easy, especially when you’re a beginner. Therefore, to avoid unexpected problems and issues, we highly recommend you contact professional developers. In this case, you should contact ArrowHitech – one of the best outsourcing IT in Vietnam. Having more than 12 years of experience, we can help you handle difficulties in not only coding, but also in eCommerce. What are you waiting for? Contact us here or via email: support@arrowhitech.com or hotline + 84 243 7955 813

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