/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 vote247 views1 answer
How to check if variable in python is of what kind
Python
0 vote237 views1 answer
Python emoji convert
Python
0 vote275 views1 answer
Form rendering options in django
Python
15 votes239 views3 answers
Import numpy
Python
0 vote244 views1 answer
Df.rename(index=str, columns={"A": "a", "C": "c"}) what does index=str means
Python
0 vote244 views1 answer
Powershell open file with default program
Python
8 votes282 views4 answers
Glob
Python
0 vote274 views1 answer
Percentage change between the current and the prior element.
Python
0 vote271 views1 answer
How to fill a shape with colour in python turtle
Python
0 vote254 views1 answer
Python digit string
Python