Python list with None

Find indices with None values in given list in Python

Manytime when dealing with data analysis we may come across the None values present in a list. These values can not be used directly in mathematical operations and string operations etc. So we need to find their position and either convert them or use them effectively.

With range[]

Combining the range and len function we can compare the value of each element with None and capture their index positions. Of course we use a for loop design to achieve this.

Example

Live Demo

listA = ['Sun', 'Mon',None, 'Wed', None, None] # Given list print["Given list : ",listA] # Using range positions = [i for i in range[len[listA]] if listA[i] == None] # Result print["None value positions : ",positions]

Output

Running the above code gives us the following result

Given list : ['Sun', 'Mon', None, 'Wed', None, None] None value positions : [2, 4, 5]

With enumerate

We can also use the enumerate function which lists out ech element. Then we compare each element with the None value and select its position as shown below in the program.

Example

Live Demo

listA = ['Sun', 'Mon',None, 'Wed', None, None] # Given list print["Given list : ",listA] # Using enumarate positions = [i for i, val in enumerate[listA] if val == None] # Result print["None value positions : ",positions]

Output

Running the above code gives us the following result

Given list : ['Sun', 'Mon', None, 'Wed', None, None] None value positions : [2, 4, 5]