/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

1 vote217 views1 answer
Access-Control-Allow-Origin django
Python Django
0 vote182 views1 answer
Qq plot using seaborn
Python
68 votes222 views6 answers
Python create directory
Python
2 votes207 views3 answers
How to sum digits of a number in python
Python
0 vote179 views1 answer
Raising a new style class which doesn't inherit from baseexception python
Python
19 votes129 views2 answers
Append dataframe pandas
Python
12 votes184 views4 answers
Install numpy
Python
1 vote194 views2 answers
How to 404 custom page not found in django
Python
0 vote203 views1 answer
Python font
Python
1 vote201 views2 answers
How to 404 custom page not found in django
Python Django