Replace All Instances of Characters in a String – Python

January 21, 2023

Here is a simple way to replace all instances of characters in a string in Python:

final_string = original_string.replace('original_value', 'new_value')

And if you want to replace n number of instances (where n is the number of instances needed):

final_string = original_string.replace('original_value', 'new_value', n)

Examples of Replacing Instances of Characters in a String in Python

Example 1: Simple replacement of instances in a string

Let’s suppose that you have the following string:

original_string = 'aayyccyyeeyy'

print(original_string)

Here is the original string:

aayyccyyeeyy

Now let’s say that you wish to replace all instances of ‘yy‘ with ‘xx‘.

Here is the script that you may use to perform the replacement:

original_string = 'aayyccyyeeyy'
final_string = original_string.replace('yy', 'xx')

print(final_string)

As you can see, all the instances of ‘yy’ were replaced with ‘xx’ as follows:

aaxxccxxeexx

Example 2: Replacement of n instances

Now let’s replace only the first 2 instances of yy with xx:

original_string = 'aayyccyyeeyy'
final_string = original_string.replace('yy', 'xx', 2)

print(final_string)

Notice that only the first 2 instances of ‘yy’ (out of 3 instances) were replaced:

aaxxccxxeeyy

Example 3: Replacement of special characters

The same principles covered above can be applied when replacing special characters.

For example, let’s replace all instances of ‘:’ with ‘,’ as follows:

original_string = 'aa:cc:ee'
final_string = original_string.replace(':', ',')

print(final_string)

The result:

aa,cc,ee

And if you want to replace only the first 2 instances:

original_string = 'aa:cc:ee:dd'
final_string = original_string.replace(':', ',', 2)

print(final_string)

The result:

aa,cc,ee:dd