python merge tuples elements with index/key

Question

I’m trying to merge columns values from tuples with an index:

source tuples with a lot of timestamps (1440 ~):

tuples = [('2022-10-15 01:16:00', '5', '', '', 'hdd1', '1234'),
          ('2022-10-15 01:16:00', '', '4', '', 'hdd1', '1234'),
          ('2022-10-15 01:17:00', '10', '', '', 'hdd1', '1234'),
          ('2022-10-15 01:17:00', '', '25', '', 'hdd1', '1234'),
          ('2022-10-15 01:18:00', '1', '', '', 'hdd1', '1234'),
          ('2022-10-15 01:18:00', '', '2', '', 'hdd1', '1234'),
          ...]

the index is the first element.

desired tuples output:

[('2022-10-15 01:16:00', '5', '4', '', 'hdd1', '1234'),
 ('2022-10-15 01:17:00', '10', '25', '', 'hdd1', '1234'),
 ('2022-10-15 01:18:00', '1', '2', '', 'hdd1', '1234')]

my code:

tuples =   [('2022-10-15 01:16:00', '5', '', '', 'hdd1', '1234'), ('2022-10-15 01:16:00', '', '4', '', 'hdd1', '1234'),('2022-10-15 01:17:00', '10', '', '', 'hdd1', '1234'), ('2022-10-15 01:17:00', '', '25', '', 'hdd1', '1234'), ('2022-10-15 01:18:00', '1', '', '', 'hdd1', '1234'), ('2022-10-15 01:18:00', '', '2', '', 'hdd1', '1234')]
result = []
key = lambda t: t[0]
for letter,items in itertools.groupby(sorted(tuples,key=key),key):
    items = list(items)
    if len(items) == 1:
        result.append(items[0]+(0,0))
    else:
        result.append(items[0]+items[1][1:])
print(result)

many thanks for any help

Asked By: Indi59

||

Source

Answer 1

I think something like this is what you want:

from itertools import groupby
result = []
key = lambda t: t[0]
for _,items in groupby(sorted(tuples, key=key), key):
    item = None
    for i, it in enumerate(items):
        # First item in group. Need to convert to list to edit.
        if not item: item = list(it)
        # Not first. Update item at correct index.
        else: item[1 + i] = it[1 + i]
    # Convert back to tuple and save.
    result.append(tuple(item))

for item in result: print(item)

Output:

('2022-10-15 01:16:00', '5', '4', '', 'hdd1', '1234')
('2022-10-15 01:17:00', '10', '25', '', 'hdd1', '1234')
('2022-10-15 01:18:00', '1', '2', '', 'hdd1', '1234')

Answered By: Johnny Mopp

Answer 2

Here is a solution using a dictionary to store the date while iterating over the tuples.

#empty dict with date as key and a list placeholder as value
r = {t[0]:["", "", "", "", ""] for t in tuples} 


#iterate over the tuples and populate the dict
for (date, *other_fields) in tuples:
    for i, value in enumerate(other_fields):
        if value: #skip if it's empty
            r[date][i] = value


#convert the dictionary in a list of tuples
r = [tuple([k, *v]) for k,v in r.items()]
print(r)

#[('2022-10-15 01:16:00', '5', '4', '', 'hdd1', '1234'), ('2022-10-15 01:17:00', '10', '25', '', 'hdd1', '1234'), ('2022-10-15 01:18:00', '1', '2', '', 'hdd1', '1234')]

Answered By: alec_djinn

python merge tuples elements with index/key

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