How to Change the Length of a String in Python

In Python, a string is a sequence of characters and it’s one of the sequence data types in Python. It’s immutable, meaning you cannot change an existing string. But sometimes, you might need to alter the length of a string.

Although you can’t directly change the length of a string, there are workarounds that allow you to effectively change a string’s length.

Step 1: Measure the Length of Your String

When you want to change the length of a string, first you’ll want to know what length it currently is. In Python, we measure the length of a string using the built-in len() function.

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my_string = 'Hello, World!'
print(len(my_string))

This code will print ’13’, as it is counting both the characters and spaces in the string.

Step 2: Add to Your String

One way to increase the length of a string is to add more characters to it. In Python, you can concatenate strings using the plus sign (+).

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my_string = 'Hello, World!'
my_string += ' Nice to meet you.'
print(len(my_string))

Now, the output will be ’32’. We’ve successfully increased the length of the string by adding additional phrases.

Step 3: Trim Your String

If you want to decrease the length of a string, you can remove characters from it. Python strings support slicing, which means you can pick a part of the string using it’s index.

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my_string = 'Hello, World!'
my_string = my_string[:5]
print(len(my_string))

This time around, the output will be ‘5’. This cuts off anything in the string after the fifth character.

Step 4: Replace Characters in your String

You can also change the length of a string by replacing parts of it using the replace() function. It allows you to replace specified parts of a string with the text of your choice.

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my_string = 'Hello, World!'
my_string = my_string.replace('Hello, World!', 'Hii!')
print(len(my_string))

The output will be ‘4’. Here we’ve replaced and shortened the entire string with a new one.

Full Code

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my_string = 'Hello, World!'
print(len(my_string))
 
my_string += ' Nice to meet you.'
print(len(my_string))
 
my_string = my_string[:5]
print(len(my_string))
 
my_string = my_string.replace('Hello, World!', 'Hii!')
print(len(my_string))
 
13
31
5
5

Conclusion

The length of a string is an essential attribute in many programming scenarios. Python doesn’t provide a direct method to modify the length of a string as it’s an immutable type of variable.

However, this tutorial showcased how you can increase and decrease the length of a string using various methodologies such as concatenation, slicing, and replacing, providing you with the desired result.