KwickClips Python · 42 sec · free
Why does the old item stay in a list default?
Short answer. The default list is made once and shared by every call.
How do you fix it?
Use bag=None and make a new list inside the function.
The fix
| Write bag=None |
| Inside: if bag is None: bag = [] |
A fresh call, an empty bag. So why is the old pen still inside? A list default is made once, when def runs. Every call shares that list. So book joins pen. The fix. Write bag equals None. Inside, make a new list when bag is None.
This clip is from the full lesson: Function Arguments: Positional, Default and Keyword Parameters — 7 minutes, with the tables, the quick answers and the whole lesson in text.
Useful for: CBSE Class 12 Computer Science (083), Programming All levels Python
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