CODEWITHSUNDEEP
pythondictionarymatch
Rookierookie
Rookierookie

Reputation: 177

Iterating through two lists that contain dictionaries, appending matches to a third list

I have two lists that contain dictionaries:

list105 = [
{'Country': 'Zimbabwe', 'GDP/Pop 2005': 281.0751453319367}
{'Country': 'Zambia', 'GDP/Pop 2005': 654.055392253311}
{'Country': 'Congo (Dem. Rep.)', 'GDP/Pop 2005': 115.37122637190915}
]

list202 = [
{'Country': 'Vietnam', 'GDP/Pop 2002': 633.4709249146734}
{'Country': 'Zambia', 'GDP/Pop 2002': 1198.4556066429468}
{'Country': 'Vanuatu', 'GDP/Pop 2002': 1788.4344216880352}
]

Is it possible to iterate through both lists of dictionaries, match the 'Country' key, and append all unique keys from either dictionary to a new dictionary created in the third list?E.g. following from above, the third list would contain:

list2and3 = [
{'Country': 'Zambia', 'GDP/Pop 2005': 654.055392253311, 'GDP/Pop 2002': 1198.4556066429468}
]

I've started off with something like:

list2and3 = []
for line in list105:
    for row in list202:
        if line['Country'] == row['Country']:
            #do something and append to list2and3

Upvotes: 3

Views: 2553

Answers (3)

zhangyangyu
zhangyangyu

Reputation: 8610

You may want a better solution without loop.

[x for x in list105 for y in list202 if x['Country'] == y['Country'] and x != y and not x.update(y)]

1 list comprehesion can lead you to the answer but it may be not human-friendly. Just choose what you like.

Upvotes: 0

georg
georg

Reputation: 214959

Convert the first list to a dict:

d = {x['Country']:x for x in list105}

Then iterate the second list and add data to the dict:

for item in list202:
    key = item['Country']
    if key in d:
        d[key].update(item)
    else:
        d[key] = item

Finally, apply .values() to convert the dict back to a list:

newlist = d.values()

Note: this data structure is sub-optimal, consider rethinking it.

Upvotes: 1

Ashwini Chaudhary
Ashwini Chaudhary

Reputation: 250981

from copy import deepcopy
list2and3 = []
for line in list105:
    for row in list202:
        if line['Country'] == row['Country']:
            dic = deepcopy(line) # creates a deepcopy of row, so that the
            dic.update(row)      # update operation doesn't affects the original object
            list2and3.append(dic)

print list2and3

output:

[{'Country': 'Zambia', 'GDP/Pop 2005': 654.055392253311, 'GDP/Pop 2002': 1198.4556066429468}]

Upvotes: 0

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