Merging tuples together-CodePudding

When I query my Mysql table to get results. I get a tuple back.

The tuple is like this:

(('Book 1', 1), ('Book 2', 1), ('Book 1', 2))

How do I get my tuple to be like this:

(('Book 1', 3), ('Book 2', 1))

Any suggestions in python or SQL would be helpful.

CodePudding user response：

you can try SQL group by statement with aggregate function 'sum' example

select book_name,sum(book_quantity) 
from your_table_name 
group by book_name

CodePudding user response：

Use a dictionary to implement counting and then switch back to tuples

result = {}
tuple_ = (('Book 1', 1), ('Book 2', 1), ('Book 1', 2))
for k, v in tuple_:
    result[k] = result.setdefault(k, 0)   v

print(tuple(result.items()))  # (('Book 1', 3), ('Book 2', 1))

Use defaultdict

from collections import defaultdict

result = defaultdict(int)
for k, v in tuple_:
    result[k]  = v

print(tuple(result.items()))