CODEWITHSUNDEEP
pythonpython-3.xdictionarynested
col. slade
col. slade

Reputation: 451

Python3: Add to dictionaries in list, based on other dictionaries

I am trying to learn / teach myself Python3 and I'm working on reformatting scraped web data.

Input is a list of dictionaries:

[{'name' : 'Anna', 'gender': "f", 'ID': 512128, 'age' : 28}, 
 {'name' : 'Barney', 'gender': "m", 'ID': 012428, 'age' : 29},
 {'name' : 'Cesar', 'gender': "m", 'ID': 032536, 'age' : 57}]

I would like to achieve a list of dictionaries with every dictionary having an additional field names 'colleagues', which contains the information of the other dictionaries in the list.

Desired output:

[{'name' : 'Anna', 'gender': "f", 'ID': 512128, 'age' : 28, 'colleagues' : [{'name' : 'Barney', 'gender': "m", 'ID': 012428, 'age' : 29}, {'name' : 'Cesar', 'gender': "m", 'ID': 032536, 'age' : 57}]}, 
 {'name' : 'Barney', 'gender': "m", 'ID': 012428, 'age' : 29, 'colleagues' : [{'name' : 'Anna', 'gender': "f", 'ID': 512128, 'age' : 28}, {'name' : 'Cesar', 'gender': "m", 'ID': 032536, 'age' : 57}]},
 {'name' : 'Cesar', 'gender': "m", 'ID': 032536, 'age' : 57, 'colleagues' : [{'name' : 'Anna', 'gender': "f", 'ID': 512128, 'age' : 28},  {'name' : 'Barney', 'gender': "m", 'ID': 012428, 'age' : 29}]}]

As you can tell, I am new to python but understand simple comprehension and for loops.. etc. I spent the last night with all possible attempts and very nested loop structures - which were causing infinite loops.

I hope one of the experts can help me how to approach that task, any help is greatly appreciated.. Thanks!

Upvotes: 0

Views: 48

Answers (1)

Amadan
Amadan

Reputation: 198324

output = [dict([*p.items(),
                ['colleagues', [q for q in input if p != q]]
               ]) for p in input]

You might be able to speed it up by using sets and inputset - set(p).

The whole dict([*p.items(), [k, v]]) is kind of a hack to make a new dict with an extra key-value pair without having to use statements. It is pretty much equivalent to dict_with_new_pair(p, k, v) given:

def dict_with_new_pair(d, k, v):
    from copy import copy
    c = copy(d)
    c[k] = v
    return c

EDIT: As you said, both p and q are elements of input. The expression parses like this: For every person p in input, enrich it with key colleagues, whose value will be the all persons q in input that are not p (and collect the list of all such enriched p into a new list output).

Upvotes: 1

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