Shulou(Shulou.com)06/01 Report--

This article mainly explains "Python how to solve the empty list to append output to None", interested friends may wish to have a look. The method introduced in this paper is simple, fast and practical. Next let the editor to take you to learn "Python how to solve the empty list append output to None" it!

The function you want to achieve

Number of additions in empty list

Original code:

FitnessBest = [] FitnessBest = FitnessBest.append (fitnessVal [0,0]) print (FitnessBest)

Output:

None

Solution.

Analysis:

Be careful! The append method simply modifies the original list in the right place!

This means that instead of returning a list, he just modifies the original list, so if you use the equation output, the return is None, which means there is no return value!

In other words, remove the return value to get a new list!

Modified code:

FitnessBest = [] FitnessBest.append (fitnessVal [0,0]) print (FitnessBest)

Content supplement:

Analysis of problems

Considerations for using append:

The append method simply modifies the original list in the right place!

That is, instead of returning a list, it just modifies the original list, so if you use equation output, the return is None.

Remove the return value to get a new list!

Modified code:

List= [1, 2, 3, 4] list.append (5) print (list)

Output:

1,2,3,4,5

At this point, I believe you have a deeper understanding of "Python how to solve the empty list appended output to None", might as well come to the actual operation! Here is the website, more related content can enter the relevant channels to inquire, follow us, continue to learn!

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.