How to compare srings in Python? Developer point heading

How To Compare String In Python? (String
Comparison 101)

In this article, we will be learning about strings in programming, how to create them, and their uses. We will also be exploring various operators for comparing strings in Python. Lastly, we will look at some examples of Python string comparison and its corresponding output.

What are strings?

In Python, strings are sequences of characters. They are used to represent text and can contain letters, numbers, and symbols. Strings are surrounded by either single or double quotes. For example:

"Hello, world!"
'Hello, world!'

Another example is in the English language, we have 26 characters. However, computers don’t understand characters and instead work with binary numbers (0s and 1s). The process of Converting characters to binary numbers is called encoding, and the reverse process is called decoding. Some popular encodings include ASCII and Unicode. In Python, strings are sequences of Unicode characters.

Now, let’s look at some operators for comparing strings in Python:
==: This operator checks if two strings are equal.

  • !=: This operator checks if two strings are not equal.
  • <: This operator checks if the string on the left is smaller than the string on the right (based on the ASCII/Unicode values of the characters).
  • <=: This operator checks if the string on the left is smaller than or equal to the string on the right.
  • >: This operator checks if the string on the left is greater than the string on the right.
  • >=: This operator checks if the string on the left is greater than or equal to the string on the right.

String Equals Check in Python

In Python, you can check if two strings are equal using the == operator. This operator
compares the values of the strings and returns True if they are the same, and False if they are
not.
Here is an example of using the == operator to check if two strings are equal:

 

string1 = "Hello"
string2 = "Hello"
if string1 == string2:
print("The strings are equal.")
else:
print("The strings are not equal.")

Output:

 The strings are equal.

In this example, the if statement will be evaluated as True because the values of string1 and string2 are both ”Hello”. The code will output ”The strings are equal.” You can also use the != operator to check if two strings are not equal. For example:

string1 = "Hello"
string2 = "World"
if string1 != string2:
print("The strings are not equal.")
else:
print("The strings are equal.")

Output:

The strings are not equal.

In this case, the if statement will be evaluated as True because the values of string1 and string2 are different. The code will output ”The strings are not equal.” It’s important to note that the == and != operators are case-sensitive, meaning that ”hello” is not considered equal to ”Hello”. If you want to compare strings regardless of the case, you can use the lower() or upper() method to convert both strings to the same case before performing the comparison.

What about Case insensitive comparisons

In some cases, you may want to compare two strings while ignoring the case of the characters. For example, you may want to consider ”Hello” and ”hello” to be equal. There are a few different ways you can perform case-insensitive comparisons in Python. One option is to use the lower() or upper() method to convert both strings to the same case before performing the comparison. Here is an example using the lower() method:

string1 = "Hello"
string2 = "hello"
if string1.lower() == string2.lower():
print("The strings are equal.");
else:
print("The strings are not equal.");


In this example, both string1 and string2 are converted to lowercase using the lower() method before the comparison is performed. The if the statement will be evaluated as True because the lowercase versions of string1 and string2 are the same, and the code will output ”The strings are equal.” You can also use the upper() method in the same way to compare strings while ignoring cases:

string1 = "Hello"
string2 = "hello"
if string1.upper() == string2.upper();
print("The strings are equal.");
else:
print("The strings are not equal.");

In this case, both strings will be converted to uppercase using the upper() method before the comparison is performed. The if statement will again be evaluated as True and the code will output ”The strings are equal.” Another option for performing case-insensitive comparisons is to use the casefold() method.

This method is similar to lower(), but is more aggressive in the characters it converts, making it is suitable for certain language-specific case mappings. Here is an example using casefold():


string1 = "Hello" string2 = "hello" if string1.casefold() == string2.casefold():
print("The strings are equal.")
else:
print("The strings are not equal.")
This code will also output ”The strings are equal.”

It’s important to note that these methods do not modify the original strings; they only return new strings with the modified case. If you want to permanently modify a string, you can assign the result of the method to the original string:


string1 = "Hello"
string2 = "hello"
string1 = string1.lower()
string2 = string2.lower()
if string1 == string2:
print("The strings are equal.");
else:
print("The strings are not equal.");

This code will also output ”The strings are equal.” You can also use the == and != operators with the str.casefold() method to perform case insensitive comparisons. For example:


string1 = "Hello"
string2 = "hello"
if string1.casefold() == string2.casefold(): print("The strings are equal.")
else: print("The strings are not equal.")

This code will also output ”The strings are equal.” I hope this helps! Let me know if you have any further questions.

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