/Python/Append to a ldictionary value list

Append to a ldictionary value list

#list.append returns None, since it is an in-place operation and you are 
#assigning it back to dic[key]. So, the next time when you do 
#dic.get(key, []).append you are actually doing None.append. 
#That is why it is failing. Instead, you can simply do
dates_dict.setdefault(key, []).append(date)
#or 
from collections import defaultdict
dates_dict = defaultdict(list)
for key, date in cur:
    dates_dict[key].append(date)

Source: stackoverflow.com

Similar codes

0 vote182 views1 answer
How to upload files and folders with pygithub
Python
1 vote164 views1 answer
How to import a module with a string?
Python
0 vote175 views2 answers
Pip install covid
Python
0 vote200 views1 answer
Sqlalchemy filter getattr
Python
0 vote170 views1 answer
Python how to sort a list alphabetically
Python
3 votes159 views6 answers
Fizz buzz python
Python
8 votes161 views5 answers
What is module in python
Python
0 vote166 views1 answer
Python string: .title()
Python
0 vote147 views1 answer
See you tomorrow in italian
Python
2 votes452 views4 answers
Python how to count items in array
Python