Python defaultdict(list)

>>> s = [('yellow', 1), ('blue', 2), ('yellow', 3), ('blue', 4), ('red', 1)]
>>> d = defaultdict(list)
>>> for k, v in s:
...     d[k].append(v)
...
>>> d.items()
[('blue', [2, 4]), ('red', [1]), ('yellow', [1, 3])]

Source: docs.python.org

.defaultdict

>>> from collections import defaultdict
>>> food_list = 'spam spam spam spam spam spam eggs spam'.split()
>>> food_count = defaultdict(int) # default value of int is 0
>>> for food in food_list:
...     food_count[food] += 1 # increment element's value by 1
...
defaultdict(<type 'int'>, {'eggs': 1, 'spam': 7})
>>>

Source: accelebrate.com

Similar codes

1 vote102 views1 answer
Matplotlib remove x and y labels
Python
-4 votes210 views1 answer
Hello world python 2
Python
3 votes131 views1 answer
Dns request scapy
Python
0 vote126 views1 answer
Spansk dansk
Python
0 vote91 views1 answer
Python compare bytes
Python
0 vote129 views1 answer
Disable console messages in Flask server
Python
0 vote159 views1 answer
Boston data set to pandas df
Python
1 vote130 views1 answer
Python web parser
Python
0 vote149 views1 answer
Add up all the numbers in each row and output that number output the grand total of all rows
Python
1 vote138 views1 answer
Python better while loop that count up
Python