Merging array elements based on other arrays elements in Python

Question

I have a data structure which the output looks like below:

['409597', ['You'], '409597', ['matter'], '409597', ['manager'], '809558', ['metro'], '809558', ['station'], '829258', ['bucket'], '829258', ['water'], '867297'..........]

I want to find a way to make this into several arrays which are merged based on the id number. The format I want is as follow:

['You','matter','manager'],
['metro','station'],
['bucket','water'],
...........

How can I achieve such a list of arrays (in Python) based on the similar ID of the original output I have?

how did you end up with that wierd data structure in the first place? — vishal
– vishal, Commented Jul 30, 2018 at 10:37
my original was a query of dict format as follow: [{'Instant_ID': 409597}, {'Token': 'You'}] [{'Instant_ID': 409597}, {'Token': 'matter'}] [{'Instant_ID': 409597}, {'Token': 'manager'}] [{'Instant_ID': 809558}, {'Token': 'metro'}] [{'Instant_ID': 809558}, {'Token': 'station'}] [{'Instant_ID': 829258}, {'Token': 'bucket'}] [{'Instant_ID': 829258}, {'Token': 'water'}] — Fasa
– Fasa, Commented Jul 30, 2018 at 10:39

Sunitha · Accepted Answer · 2018-07-30 10:53:08Z

Use zip_longest to create key-value pairs of elements and then use itertools.groupby to group them together based on the key.

>>> from itertools import groupby
>>> l = ['409597', ['You'], '409597', ['matter'], '409597', ['manager'], '809558', ['metro'], '809558', ['station'], '829258', ['bucket'], '829258', ['water']]
>>> [[e[1][0] for e in list(v)] for k,v in groupby(zip_longest(*([iter(l)]*2)), lambda x: x[0])]
[['You', 'matter', 'manager'], ['metro', 'station'], ['bucket', 'water']]

Actually, it is slightly easier to work with your original list of dict.

ld = [[{'Instant_ID': 409597}, {'Token': 'You'}], [{'Instant_ID': 409597}, {'Token': 'matter'}], [{'Instant_ID': 409597}, {'Token': 'manager'}], [{'Instant_ID': 809558}, {'Token': 'metro'}], [{'Instant_ID': 809558}, {'Token': 'station'}], [{'Instant_ID': 829258}, {'Token': 'bucket'}], [{'Instant_ID': 829258}, {'Token': 'water'}]]
>>> [[e[1]['Token'] for e in v] for k,v in groupby(ld, lambda x: x[0]['Instant_ID'])]
[['You', 'matter', 'manager'], ['metro', 'station'], ['bucket', 'water']]

Rakesh · Accepted Answer · 2018-07-30 10:52:34Z

0

From your source.

from itertools import groupby

l = [[{'Instant_ID': 409597}, {'Token': 'You'}], [{'Instant_ID': 409597}, {'Token': 'matter'}], [{'Instant_ID': 409597}, {'Token': 'manager'}], [{'Instant_ID': 809558}, {'Token': 'metro'}], [{'Instant_ID': 809558}, {'Token': 'station'}], [{'Instant_ID': 829258}, {'Token': 'bucket'}], [{'Instant_ID': 829258}, {'Token': 'water'}]]
print([[i[1]["Token"] for i in value] for key, value in groupby(l, lambda x: x[0]["Instant_ID"])])

Output:

[['You', 'matter', 'manager'], ['metro', 'station'], ['bucket', 'water']]

answered Jul 30, 2018 at 10:52

Rakesh

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Vasilis G. · Accepted Answer · 2018-07-30 10:56:13Z

0

You can do it using pure Python as well:

inList = ['409597', ['You'], '409597', ['matter'], '409597', ['manager'], '809558', ['metro'], '809558', ['station'], '829258', ['bucket'], '829258', ['water']]
#Find all number strings
numbers = sorted(set([inList[i] for i in range(0,len(inList),2)]))
#Create lists based on these number strings
newLists = [[inList[i][0] for i in range(1,len(inList),2) if inList[i-1]==number] for number in numbers]
print(newLists)

Output:

[['You', 'matter', 'manager'], ['metro', 'station'], ['bucket', 'water']]

answered Jul 30, 2018 at 10:56

Vasilis G.

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