Merging two list of dictionary in python

Question

lst1 = [
    {'mem': '20.0', 'name': 'p1', 'cpu': '20.0'}, 
    {'mem': '20.0', 'name': 'p2', 'cpu': '20.0'},
    {'mem': '20.0', 'name': 'p3', 'cpu': '20.0'}, 
    {'mem': '20.0', 'name': 'p4', 'cpu': '20.0'}
]

lst2 = [
    {'pid': 814, 'name': 'p1'},
    {'pid': 999, 'name': 'p2'},
    {'pid': 1006, 'name': 'p3'},
    {'pid': 1152, 'name': 'p4'}
]

I need to merge above two list into single list i.e.

lst3 = [
    {'mem': '20.0', 'name': 'p1', 'cpu': '20.0', 'pid':814}, 
    {'mem': '20.0', 'name': 'p2', 'cpu': '20.0','pid':999},
    {'pid': 1006, 'mem': '20.0', 'name': 'p3', 'cpu': '20.0'},
    {'pid': 1152,'mem': '20.0', 'name': 'p4', 'cpu': '20.0'}
]

I have tried doing it in below way

lst3 = list()
test = dict()
for f,b in zip(lst1,lst2):
    test = f.copy()
    test.update(b)
    #print test
    lst3.append(test)

print lst3

Please let me know is there any easy method or more pythonic way to do this

Possible duplicate of How to concatenate two lists in Python? — peachykeen
– peachykeen, Commented Jun 27, 2018 at 18:29
Possible duplicate of join two lists of dictionaries on a single key — tourist
– tourist, Commented Jun 27, 2018 at 18:38

user3483203 · Accepted Answer · 2018-06-27 18:41:42Z

2

Just use zip and merge, as long as both lists are ordered relative to each other:

out = [{**i, **j} for i, j in zip(lst1, lst2)]

# Result

[{'cpu': '20.0', 'mem': '20.0', 'name': 'p1', 'pid': 814},
 {'cpu': '20.0', 'mem': '20.0', 'name': 'p2', 'pid': 999},
 {'cpu': '20.0', 'mem': '20.0', 'name': 'p3', 'pid': 1006},
 {'cpu': '20.0', 'mem': '20.0', 'name': 'p4', 'pid': 1152}]

Matches output:

In [292]: out == lst3
Out[292]: True

If the lists are not guaranteed to be sorted, you can sort on the common key, in this case name, before applying my method:

lst1, lst2 = (sorted(i, key=lambda x: x['name']) for i in [lst1, lst2])

Personally, I think your current method works fine, and it is very clear what you are doing. Also, my method of merging exclusively works in Python 3.5+

edited Jun 27, 2018 at 18:41

answered Jun 27, 2018 at 18:30

user3483203

51.3k10 gold badges72 silver badges104 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Soudipta Dutta · Accepted Answer · 2022-12-17 09:09:00Z

0

l1 = [{'id': 1, 'name': 'test'}, {'id': 2, 'name': 'test1'}]
l2 = [{'id': 3, 'age': 10},{'id': 4, 'age': 10},{'id': 1, 'age': 10}, {'id': 2, 'age': 20}]


def m1(l1,l2):
    d = defaultdict(dict)
    for l in (l1,l2):
        for d1 in l :
            d[d1['id']].update(d1)
    aa = sorted(d.values(),key = itemgetter('id'))
    aap = print(aa)
    return aap        
            
m1(l1,l2)            
                        
"""
output :
[{'id': 1, 'name': 'test', 'age': 10}, {'id': 2, 'name': 'test1', 'age': 20}, {'id': 3, 'age': 10}, {'id': 4, 'age': 10}]
"""

answered Dec 17, 2022 at 9:09

Soudipta Dutta

2,0701 gold badge16 silver badges11 bronze badges

Collectives™ on Stack Overflow

Merging two list of dictionary in python

2 Answers 2

Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related