从元组列表字典创建CSV文件

Question

I would like to take this dictionary I have:

    table = {2015-11-10:[('pear', 22), ('banana', 50)], 
    2015-11-13:[('banana', 22), ('apple', 50), ('strawberry', 30), ('pear', 35), ('orange', 2), ('mango', 76)]
    2015-11-12:[('banana', 22), ('orange', 50), ('mango', 30), ('strawberry', 35)]
    }

    with open ('transaction.csv', 'wb') as f:
        w = csv.writer(f, delimiter = ',')
        w.writerow(['transaction_date', 'fruits', 'quantity'])
        for k,v in table.items():
            w.writerow([k,v])

What I want to be printed is that each key, aka date has only one pair of tuples such that there are only three columns. However I keep having it be printed out as:

    2015-11-10,"[('pear', 22), ('banana', 50)]"
    2015-11-13,"[('banana', 22), ('apple', 50), ('strawberry', 30), ('pear', 35), ('orange', 2), ('mango', 76)]"
    2015-11-12,"[('banana', 22), ('orange', 50), ('mango', 30), ('strawberry', 35)]"

Instead of this:

    2015-11-10,pear,22
    2015-11-10,banana,50
    2015-11-13,banana,22

And so on.

Any help would definitely be appreciated. Thank you.

Answer 1

The data structure is nested. You need an inner loop over the fruits and quantities:

import csv

table = {"2015-11-10": [('pear', 22), ('banana', 50)],
         "2015-11-13": [('banana', 22), ('apple', 50), ('strawberry', 30), ('pear', 35), ('orange', 2), ('mango', 76)],
         "2015-11-12": [('banana', 22), ('orange', 50), ('mango', 30), ('strawberry', 35)]
         }

with open('transaction.csv', 'wb') as f:
    w = csv.writer(f, delimiter=',')
    w.writerow(['transaction_date', 'fruits', 'quantity'])

    for transaction_date, fruits in table.items():
        for fruit, quantity in fruits:
            w.writerow([transaction_date, fruit, quantity])

Here is what I have inside the transaction.csv after running the code:

transaction_date,fruits,quantity
2015-11-10,pear,22
2015-11-10,banana,50
2015-11-13,banana,22
2015-11-13,apple,50
2015-11-13,strawberry,30
2015-11-13,pear,35
2015-11-13,orange,2
2015-11-13,mango,76
2015-11-12,banana,22
2015-11-12,orange,50
2015-11-12,mango,30
2015-11-12,strawberry,35

Answer 2

I think this will accomplish your objective. You need to also iterate over the value pairs associated with each date key:

import csv

table = {
    '2015-11-10':[('pear', 22),
                  ('banana', 50)], 
    '2015-11-13':[('banana', 22),
                  ('apple', 50),
                  ('strawberry', 30),
                  ('pear', 35),
                  ('orange', 2),
                  ('mango', 76)],
    '2015-11-12':[('banana', 22),
                  ('orange', 50),
                  ('mango', 30),
                  ('strawberry', 35)]
    }

with open ('transaction.csv', 'wb') as f:
        w = csv.writer(f, delimiter = ',')
        w.writerow(['transaction_date', 'fruits', 'quantity'])
        for date, pairs in table.items():
            for pair in pairs:
                w.writerow([date, pair[0], pair[1]])