Python | Empty String to None Conversion

Sometimes, while working with Machine Learning, we can encounter empty strings and we wish to convert to the None for data consistency. This and many other utilities can require the solution to this problem. Let’s discuss certain ways in which this problem can be solved.

Method #1 : Using lambda
This task can be performed using the lambda function. In this we check for string for None or empty string using the or operator and replace the empty string with None.

# Python3 code to demonstrate working of
# Empty String to None Conversion
# Using lambda

# initializing list of strings
test_list = ["Geeks", '', "CS", '', '']

# printing original list
print("The original list is : " + str(test_list))

# using lambda
# Empty String to None Conversion
conv = lambda i : i or None
res = [conv(i) for i in test_list]

# printing result
print("The list after conversion of Empty Strings : " + str(res))

Output :

The original list is : ['Geeks', '', 'CS', '', '']
The list after conversion of Empty Strings : ['Geeks', None, 'CS', None, None]

Method #2 : Using str()
Simply the str function can be used to perform this particular task because, None also evaluates to a “False” value and hence will not be selected and rather a string converted false which evaluates to empty string is returned.

# Python3 code to demonstrate working of
# Empty String to None Conversion
# Using str()

# initializing list of strings
test_list = ["Geeks", '', "CS", '', '']

# printing original list
print("The original list is : " + str(test_list))

# using str()
# Empty String to None Conversion
res = [str(i or None) for i in test_list]

# printing result
print("The list after conversion of Empty Strings : " + str(res))

Output :

The original list is : ['Geeks', '', 'CS', '', '']
The list after conversion of Empty Strings : ['Geeks', None, 'CS', None, None]