How to Compare Strings in Python? – Everything About String Comparison

String comparison in python

Hey readers! Are you learning to program or code? Which language do you use to code? If you code in Python, do you ever heard of a comparison of strings in python? So, by now you might have understood what our topic is. Yes, you are absolutely right! Today, our topic is Comparing Strings in python.

Many of you face difficulties and some of you might feel confused while comparing the strings while you are writing a program in python. In this article, I am going to give you complete and clear detail about the Comparison of Strings in the python programming language. So, if you don’t want to miss it, read this article carefully till the end.

What is String Comparison in Python?

String comparison generally takes place one after the other character in Python. Suppose, if there are two strings, we will compare the characters in the same positions from both the strings. If the characters fulfill the given comparison condition and are filled by the required number of characters, then you will move it to the characters in the next position. If you don’t do this, the result will be false. Now, we shall look at the simple structure of string comparison in python.

Generally, a string is an immutable object in the python programming language. Where you will give a variable as just a label to an object in the memory. Su[[pse, if you assign two variables in the same string value, they refer to the same string object in memory. This fact can be verified by checking their id() value.

If you want to check whether the two strings are equivalent to each other or not while you are comparing two strings, you need to justify which string should be greater or smaller than the other. Therefore, you need to use the comparison operator “==” to check if equality returns True if two string operands have the same id() value, or False otherwise.

Following is the simple string comparison in python:

The symbol or indication of the simple string comparison in python is given by “==”. This function is used to compare the values of two strings. You can also use this to return the function. But before that, all you need to do is you need to confirm if they are equal or not. The result will be returned as ‘True’ if the strings are equal. The result will be returned as ‘False’ if the strings are not equal. There is a small difference between the “is” function and “==” function.  That is the “is” function checks the IDs of the strings and the “==” function checks the values stored in the string.

You need to remember some points when using string comparison operators. The following are the two points that you must note down.

  • When you compare strings using different operators, you will treat the same letters in different letter cases either upper or lower as separate characters because the comparisons are case-sensitive.
  • If two characters are different, Remember that you need to compare the Unicode value when two characters are different. You need to consider the character with the smaller Unicode value as lower.
  • You need to perform the Python String comparison using equality (==) and comparison (<, >, !=, <=, >=) operators. While performing, you must use the characters in both strings.
  • Then one by one, you need to compare the characters in both the strings.
  • While you are comparing two strings, you need to identify whether the two strings are equivalent to each other or not. You should also ensure which string should be greater or smaller than the other.

Different Ways of comparing Strings in Python

In every programming language, Comparing strings is an important task to be fulfilled. Similarly, when it comes to Python, it is a fundamental task. However, there are several ways of doing it. So you can compare strings using different operators. You can select the best one depending on the use case.

Following are the different ways of comparing strings in the python programming language:

  1. python compare strings using the == and != operators
  2. python compare strings using the “is” operator
  3. python compare strings using the <, >, <=, and >= operators
  4. python compare strings ignoring whitespaces
  5. python compare strings if two strings are similar by doing fuzzy matching
  6. python compare strings using the and returns the difference
  7. python compare strings using debug when the string comparison is not working

However, all these are just headlines and you may not understand the whole concept just by looking at these headings. So, now I am going to give a brief description of all the different ways of comparing strings in the python programming language. I will also use some examples respectively so that you will understand each and every concept clearly in a better way.

1) Python compare strings using the == and != operators:

Comparing strings in python using the “==” and “!=” is the simplest way when you want to check if two strings are equal in Python. The first thing you will use is the ‘==’ operator. Otherwise, you can use the “!=” operator if you want to check using the opposite side.

Did you know that the operators ‘==’ and ‘!=’ are boolean operators that are used to return True or False for the given condition. Consider an example of comparing two strings. For suppose, If the two strings match the operator ‘==’ is used to return True, otherwise, it will return False.

Now, let us look at a python program that shows the general syntax for comparing strings to understand how to use the == and != operators.

Try to understand the following examples:

Example-1:

name1 = ‘courseone’
name2 = ‘courseone’
name1 == name2
True
name1 != Name2
False
name3 = ‘gaus’
name == name
False

In the above example, we have taken both the names in lowercase. Next, we shall try taking the lower case in one name and the upper case in another name.

Example-2:

name1 = ‘COURSEONE’
name2 = ‘courseone’
name1 == name2
False
name != name
True

I hope you have understood the working of ‘==’ and ‘!=’ operators in comparing two strings in Python. Now, let us go for another way of comparing the strings.

2) Python compare strings using the “is” operator:

This is another way to compare if two strings are equal or not. You will use the “is” operator to compare two strings in the python programming language. This way of python compare strings is different from comparison using the “==” operator. Using this operator, you can compare if two given strings are the same instance or not.

Now, let us look at a python program that shows the general syntax for comparing strings to understand how to use the “is” operator.

Try to understand the following example:

Example-1:

name1 = ‘courseone’
name2 = name1
name1 is name2
True
name3 = courseone
name1 is name3
False
 id(name1)
190340059
id(name2)
190340059
id(name3)
190340008

If you observe the above example, you can see that name3 is having a different identity and hence the result is false. So, it means we are comparing identities instead of content.

3. Python compare strings using the <, >, <=, and >= operators:

Look at the following example that shows the general syntax for comparing strings to understand how to use the “<, >, <=, and >=” operators.

name1 = ‘courseone’
name2 = ‘Arun’
name1 < name2
False
name1 > name2
True
name1 <= name2
False
name1 >= name2
True

4. Python compare strings ignoring the whitespaces:

When you want to compare two strings ignoring the space between the characters, all you have to do is to find where the spaces are and also check if there are multiple spaces in the string or not.

In the following example,  you will check the difference between the two strings if one of those two strings has spaces. So, here you can compare them by trimming both the given strings using the str.strip method and using the “==” operator.

Example-1:

 Q1 = ‘Hey, are you a developer?’
Q2 = ‘      Hey, are you a developer?   ‘
Q1.strip() == Q2.strip()
True

In the above example, the space is found only once. So, using strip() might be enough. But sometimes you find a string with multiple spaces inside it. So, at that time, str.strip won’t be enough.

Consider the following example:

Example-2:

Q1 = ‘       Hey, are you        a developer?’
Q2 = ‘Hey, are you a developer?’
s1.strip() == s2.strip()
False

In the above example, the result returned as false as we discussed above. This is because strip() can help you to remove space only once. So, let us see another example that can serve you better.

Example-3:

Q1 = ‘       Hey, are you        a developer?’
Q2 = ‘Hey, are you a developer?’
re.sub(‘s+’, ‘ ‘, s1.strip())
‘Hey, are you a developer?’
re.sub(‘s+’, ‘ ‘, s2.strip())
‘Hey, are you a developer?’
re.sub(‘s+’, ‘ ‘, s1.strip()) == re.sub(‘s+’, ‘ ‘, s2.strip())
True

5. Python compare strings if two strings are similar by doing fuzzy matching:

Here, you will check if the given two strings are almost equal or not. This is another popular string comparison method you will use in the python programming language. In this technique, you won’t compare their equality, instead, you will come to know how similar they are.

You are having two different ways to solve this problem:

  1. You can use the difflib from the standard library
  2. You can use an external library such as jellyfish

Example-1:

def is_string_similar(s1: str, s2: str, threshold: float = 0.8) -> bool
       return SequenceMatcher(a=s1, b=s2).ratio() > threshold
is_string_similar(s1=”courseone”, s2=”corseone”)
True
is_string_similar(s1=”courseone”, s2=”courseone”)
True
is_string_similar(s1=” courseone “, s2=” courseone jajdj”)
False

The above example gives you an idea about how to use difflib for comparing the given strings.

These are the different ways of comparing strings in the Python programming language. I hope, by reading this article and observing all the examples of various types, you might have cleared all your doubts regarding the python compare strings.

Also, check –

Leave a Comment

Your email address will not be published. Required fields are marked *