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python, lists, grouping

Samiulhaq Chardewall answered on April 26, 2023 Popularity 2/10 Helpfulness 1/10

answer python, lists, grouping

python, lists, grouping

Comment

adding sublist second elements if the first element of the sublist are the same

lst = [["a", 2], ["b", 4], ["a", 5], ["c", 8]]
dictionary = {} # intializing empty dictionary


for sub_list in lst:
# The following line of code first check wheater the key exists or not using dictionary.get() method.
# if the the key already exists so the value will be retrieved and added to the new value.
# if not the new value will be added to 0
  dictionary[sub_list[0]] = dictionary.get(sub_list[0], 0) + sub_list[1]

print(dictionary.items()) # Outputs: [('a', 7), ('b', 4), ('c', 8)]

# if you want to convert the inside elements of the list to list use the following code:

new_list = [list(x) for x in dictionary.items()]
print(new_list) # Outputs: [['a', 7], ['b', 4], ['c', 8]]

Popularity 2/10 Helpfulness 1/10 Language python

Source: stackoverflow.com

Tags: grouping python

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