How to create tuples inside list of tuples

My aim is to create a tuple inside another tuple, for example: (398905, 6340963, 2019) should become ((398905, 6340963), 2019)

I created a Pandas DataFrame which I converted into a list of tuples:

#create dataframe with 3 rows, 4 columns
data = {'X_coords':[398905, 492561, 496561], 'Y_coords':[6340963, 6526362, 6527362], 'YEAR': [2019, 2020, 2020], 'ID':[1,2,3]}
#to pandas dataframe
df = pd.DataFrame(data)

#creating a list of tuples from dataframe entries
df_tuple = [tuple(x) for x in df.values.tolist()]
#examine
print(df_tuple)

#prints:
[(398905, 6340963, 2019, 1), (492561, 6526362, 2020, 2), (496561, 6527362, 2020, 3)]

Considering my aim, the result should become: [((398905, 6340963), 2019, 1), ((492561, 6526362), 2020, 2), ((496561, 6527362), 2020, 3)]

What is a convenient way of achieving this?

CodePudding user response：

I think the easiest way is to do:

df_tuple = [((i[:2]),*i[2:]) for i in df.values.tolist()]

Basically saying you take the first items and put them in a tuple, then unpack the remaining items in the "larger" tuple.

CodePudding user response：

If you just want to group the first to elements of each tuple of the list, you could use a comprehension:

[((a, b),*c) for a, b, *c in df_tuples]

it gives as expected:

[((398905, 6340963), 2019, 1), ((492561, 6526362), 2020, 2), ((496561, 6527362), 2020, 3)]

CodePudding user response：

You could apply the required format and then convert tolist - i.e.

df.apply(lambda row: ((row['X_coords'], row['Y_coords']), row['YEAR'], row['ID']), axis=1).tolist()

Output

[((398905, 6340963), 2019, 1),
 ((492561, 6526362), 2020, 2),
 ((496561, 6527362), 2020, 3)]

CodePudding user response：

It is a one line solution which works directly with your data. Standard library is more than powerful for easy tasks

result = [((x, y), t, i) for x, y, t, i in zip(*[v for _, v in data.items()])]