Python replace() function

In this article, we will be understanding the functionality of Python replace() function.

Python replace() function with String

Python has in-built string.replace() function to replace a porting of a string with another string.

The string.replace() function accepts the string to be replaced and the new string which u want to replace the old string with.

Syntax:

string.replace("old string","new string", count)

• old string: The string to be replaced.
• new string: The new portion of the string that you wish to place in the old string’s position.
• count: It represents the number of times, we want the string to be replaced by the new string.

Example 1: Replacing old string with a new string passed to the function

inp_str = "Python with AskPython"
res = inp_str.replace("AskPython", "AP")
print("Original String:",inp_str)
print("Replaced String:",res)

In the above snippet of code, we have replaced the string – ‘AskPython’ with ‘AP’.

Output:

Original String: Python with AskPython
Replaced String: Python with AP

Replacing Specified Number of Instances

Now let’s use the count parameter to specify the number of instances of a string that we want to replace.

Example 2: Using count as a parameter to the replace() function

inp_str = "abcdaaseweraa"
res = inp_str.replace("a", "x",2)
print("Original String:",inp_str)
print("Replaced String:",res)

In this example, we have passed the input string as – ‘abcdaaseweraa’. Further, we have passed the character ‘a’ of the original string to be replaced by the character ‘x’.

Here, the count is set to 2 i.e. only the first two encountered character ‘a’ will be replaced by the character ‘x’. The remaining encountered ‘a’ will be unlaterted and will remain the same.

Output:

Original String: abcdaaseweraa
Replaced String: xbcdxaseweraa

Python replace() function with Pandas module

The replace() function can also be used to replace some string present in a csv or text file.

Python Pandas module is useful when it comes to dealing with data sets. The pandas.str.replace() function is used to replace a string with another string in a variable or data column.

Syntax:

dataframe.str.replace('old string', 'new string')

We will be using the following data set in the below example:

Example:

import pandas
df = pandas.read_csv("C:/IMDB_data.csv", sep=",",encoding='iso-8859-1')
df['Language']=df['Language'].str.replace("English","Hindi")

In the above snippet of code, pandas.read_csv() function is used to import and load a dataset.

As seen above in the data set, we have selected the ‘Language’ column in order to replace ‘English’ with ‘Hindi’.

Output:

Conclusion

So, as we have seen above, the Python replace() function is very useful when it comes to replacing a portion of a string for a huge data set.

I would strongly recommend the readers to go through the Pandas tutorial to learn further about how to interact with CSV files in Python.

References

• Python replace() function article on JournalDev