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How to remove None value from list in Python

青灯夜游

Jan 18, 2019 pm 03:48 PM

python

In Python we can use a for loop to traverse and filter None values, or use the filter() function to delete None values and then return a new list without None values. Below we will introduce the deletion method, I hope it will be helpful to everyone.

How to remove None value from list in Python

What is the value of None?

In Python there is a value called None, which means there is no value. None is the only value of the NoneType data type. Like the Boolean values True and False, None must have a capital N.

How to remove None value from list?

Method 1: Use a for loop to traverse and filter the None value

We can traverse the entire list and filter all The non-None value is appended to the new list, for example:

test_list = [1, None, 4, None, None, 5, 8, None] 
  
# 输出原始列表
print(str(test_list));
  
#删除列表中的None值
res = [] 
for val in test_list: 
    if val != None : 
        res.append(val);
  
# 输出新的列表
print (str(res))

Output:

How to remove None value from list in Python

Method 2 : Use the filter() function

The filter() function is used to filter the sequence, filter out elements that do not meet the conditions, and return a new list composed of elements that meet the conditions. It checks the list for any None values and removes them and forms a filtered list without None values.

test_list = [1, None, 4, None, None, 5, 8, None] 
# 输出原始列表
print(str(test_list));

#使用filter()函数，删除列表中的None值
res = list(filter(None, test_list)) 

# 输出新的列表
print (str(res ))

Output:

How to remove None value from list in Python

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