How to Replace with 0 in Python

In this tutorial, we’ll be covering an integral part of Python programming – the ability to replace values inside a data structure with ‘0’ or any other value.

This functionality is incredibly useful when dealing with data manipulation or cleaning tasks where you need to treat certain values in a specific way – zeros, for example, can be useful to indicate missing or null data values.

Step 1: Replacing Values in a List

One of the most commonly used data structures in Python is the list. Let’s start by replacing values in a list. The following example shows how we can take a Python list and replace all instances of a certain value with ‘0’.

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# Here is our sample Python list
list = [1, 2, 3, 1, 4, 5, 6, 1]
 
# Now let's replace all instances of '1' with '0'
list = ['0' if i==1 else i for i in list]

Output:

['0', 2, 3, '0', 4, 5, 6, '0']

Step 2: Replacing Values in a Dictionary

Dictionaries are also commonly used in Python. You can also replace values in a Python dictionary, similar to how we replaced values in a list.

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# Here is our sample Python dictionary
dict = {'A':1, 'B':2, 'C':3, 'D':1}
 
# Now let's replace all instances of '1' with '0'
dict = {k: ('0' if v == 1 else v) for k, v in dict.items()}

Output:

{'A': '0', 'B': 2, 'C': 3, 'D': '0'}

Full Code:

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# Replacing Values in a List
list = [1, 2, 3, 1, 4, 5, 6, 1]
list = ['0' if i==1 else i for i in list]
 
# Replacing Values in a Dictionary
dict = {'A':1, 'B':2, 'C':3, 'D':1}
dict = {k: ('0' if v == 1 else v) for k, v in dict.items()}

Output:

['0', 2, 3, '0', 4, 5, 6, '0']
{'A': '0', 'B': 2, 'C': 3, 'D': '0'}

Conclusion

Being able to replace certain values with ‘0’ (or any other specified value) is a valuable skill to have while working with Python. We often encounter data structures where such manipulation is necessary, like removing or replacing null values and outliers in data cleaning, preprocessing, and data analysis tasks.

This tutorial has demonstrated how to replace values with ‘0’ in both lists and dictionaries, two of the most common data structures in Python. Armed with this knowledge, you should now be better equipped to tackle any data manipulation tasks that come your way,