比较列表中的两个二维列表，并打印不同的行。 但没有一列

Question

the following:

gnucashumsaetze = [
 ['2020-11-27', 'Essen', '4.53'],
 ['2020-11-27', 'Essen', '10.67'],
 ['2020-11-30', 'Essen', '4.80'],
 ['2020-11-30', 'Lebensmittel', '2.78'],
 ['2020-11-30', 'Essen', '2.31'],
 ['2020-11-30', 'Kosmetik', '5.58'],
 ['2020-12-01', 'Essen', '11.23'],
]

onlineumsaetze = [
['2020-11-27', 'EDEKA ERNST HAUPTBAHNH  / MUENCHEN', '4.53']
['2020-11-27', 'Netto Marken-Discount  / Ingolstadt', '10.67']
['2020-11-30', 'MUELLER GMBH & CO.KG  / NUERNBERG', '4.80']
['2020-11-30', 'Netto Marken-Discount  / Frankfurt', '2.31']
['2020-11-30', 'Rossmann 2380  / Ingolstadt', '5.58']
['2020-11-30', 'ALIEXPRESS.COM  / Luxembourg', '22.46']
['2020-12-01', 'EDEKA BRAUN  / INGOLSTADT', '11.23']
['2020-12-02', 'EDEKA ERNST HAUPTBAHNH  / MUENCHEN', '7.03']
]

i would like to compare two 2d lists and output the different. But the second column (row[1]) should not be compared. Like this:

['2020-11-30', 'ALIEXPRESS.COM  / Luxembourg', '22.46']
['2020-12-01', 'EDEKA BRAUN  / INGOLSTADT', '11.23']
['2020-12-02', 'EDEKA ERNST HAUPTBAHNH  / MUENCHEN', '7.03']

what I have already tried is this; unfortunately a catastrophe:

fehlende_rows = (set((row[0] for row in onlineumsaetze),(row[2] for row in onlineumsaetze)) - set((row[0] for row in gnucashumsaetze),(row[2] for row in gnucashumsaetze)))
print(fehlende_rows)

Answer 1

I find it really helpful to write out the full loop first, and then condense it down to a list-comprehension if possible.

Probably the best way to do this would be to iterate over gnucashumsaetze and create a string->set dictionary that has dates as keys and the numbers as elements of the set.

gnucashumsaetze_dict = {}
for g in gnucashumsaetze:
    date, val = g[0], g[2]
    # Maybe you want to do val = float(g[2]) instead?
    if date not in gnucashumsaetze_dict:
        gnucashumsaetze_dict[date] = set()
    gnucashumsaetze_dict[date].add(val)

gnucashumsaetze_dict is now:

{'2020-11-27': {'10.67', '4.53'},
 '2020-11-30': {'2.31', '2.78', '4.80', '5.58'},
 '2020-12-01': {'11.23'}}

Then, iterate over each row in onlineumsaetze , and append it to the new list only if the required condition is satisfied.

new_onlineumsaetze = []
for o in onlineumsaetze:
    date, val = o[0], o[2]
    # if date is not in gnucashumsaetze_dict, return empty set
    vals = gnucashumsaetze_dict.get(date, set()) 
    if val not in vals:
        new_onlineumsaetze.append(o)

new_onlineumsaetze is now:

[['2020-11-30', 'ALIEXPRESS.COM  / Luxembourg', '22.46'],
 ['2020-12-02', 'EDEKA ERNST HAUPTBAHNH  / MUENCHEN', '7.03']]

The ['2020-12-01', 'EDEKA BRAUN / INGOLSTADT', '11.23'] row is skipped because gnucashumsaetze has an entry for ['2020-12-01', 'Essen', '11.23']

Now that you've written it as a regular for-loop, it's easier to condense this down to a list-comprehension.

new_onlineumsaetze = [o for o in onlineumsaetze if o[2] not in gnucashumsaetze_dict.get(o[0], set())]

Answer 2

For Solving this I will use list comprehension

first create two sets using only column0 and column2

gnucashumsaetze_set = set([(row[0], row[2]) for row in gnucashumsaetze])
onlineumsaetze_set = set([(row[0], row[2]) for row in onlineumsaetze])

Then we get the difference of this two sets

diff_ = onlineumsaetze_set.difference(gnucashumsaetze_set)

for the final result we look for the rows in onlineumsaetze that matches in column0 and column2 with the data we got.

res = [row for row in onlineumsaetze if (row[0], row[2]) in diff_]

print(res)

the result

[['2020-11-30', 'ALIEXPRESS.COM  / Luxembourg', '22.46'], ['2020-12-02', 'EDEKA ERNST HAUPTBAHNH  / MUENCHEN', '7.03']]