Grouping Python tuple list

Question

I have a list of (label, count) tuples like this:

[(\'grape\', 100), (\'grape\', 3), (\'apple\', 15), (\'apple\', 10), (\'apple\', 4), (\'banana\', 3)]
         


        

Answer 1

Method

def group_by(my_list):
    result = {}
    for k, v in my_list:
        result[k] = v if k not in result else result[k] + v
    return result 

Usage

my_list = [
    ('grape', 100), ('grape', 3), ('apple', 15),
    ('apple', 10), ('apple', 4), ('banana', 3)
]

group_by(my_list) 

# Output: {'grape': 103, 'apple': 29, 'banana': 3}

You Convert to List of tuples like list(group_by(my_list).items()).