'NoneType' object is not iterable
时间: 2023-10-13 07:10:35 浏览: 30
This error message typically occurs when you try to iterate over an object that is of type 'NoneType'. In Python, 'NoneType' is a special data type that represents the absence of a value, similar to 'null' in other programming languages.
For example, if you have a function that is supposed to return a list of values, but for some reason it returns 'None' instead, you may get this error when you try to iterate over the result:
```
def get_values():
# some code here
return None
values = get_values()
for value in values:
print(value)
```
In the above code, 'get_values()' returns 'None', which is not iterable. Therefore, when you try to iterate over it in the 'for' loop, you get the 'NoneType' object is not iterable error.
To fix this error, you need to make sure that the object you are trying to iterate over is not 'None'. You can use an 'if' statement to check if the object is 'None' before trying to iterate over it:
```
def get_values():
# some code here
return None
values = get_values()
if values is not None:
for value in values:
print(value)
```
In the above code, we check if 'values' is not 'None' before iterating over it. If it is 'None', we skip the 'for' loop and move on to the next statement. If it is not 'None', we iterate over it as usual.