how to merge two data structure in python

Question

I am having two complex data structure(i.e. _to and _from), I want to override the entity of _to with the same entity of _from. I have given this example.

# I am having two data structure _to and _from
# I want to override _to from _from
_to = {'host': 'test',
       'domain': [
           {
               'ssl': 0,
               'ssl_key': '',
           }
       ],
       'x': {}
       }
_from = {'status': 'on',
         'domain': [
             {
                 'ssl': 1,
                 'ssl_key': 'Xpyn4zqJEj61ChxOlz4PehMOuPMaxNnH5WUY',
                 'ssl_cert': 'nuyickK8uk4VxHissViL3O9dV7uGSLF62z52L4dAm78LeVdq'
             }
         ]
         }
### I want this output
_result = {'host': 'test',
           'status': 'on',
           'domain': [
               {
                   'ssl': 1,
                   'ssl_key': 'Xpyn4zqJEj61ChxOlz4PehMOuPMaxNnH5WUY',
                   'ssl_cert': 'nuyickK8uk4VxHissViL3O9dV7uGSLF62z52L4dAm78LeVdq'
               }
           ],
           'x': {}
           }

Use case 2:

_to = {'host': 'test',
       'domain': [
           {
               'ssl': 0,
               'ssl_key': '',
               'ssl_cert': 'nuyickK8uk4VxHissViL3O9dV7uGSLF62z52L4dAm78LeVdq',
               "abc": [],
               'https': 'no'
           }
       ],
       'x': {}
       }
_from = {
         'domain': [
             {
                 'ssl': 1,
                 'ssl_key': 'Xpyn4zqJEj61ChxOlz4PehMOuPMaxNnH5WUY',
                 'ssl_cert': 'nuyickK8uk4VxHissViL3O9dV7uGSLF62z52L4dAm78LeVdq'
             }
         ]
         }

dict.update(dict2) won't help me, because this will delete the extra keys in _to dict.

possible duplicate of [Python append dictionary to dictionary](http://stackoverflow.com/questions/8930915/python-append-dictionary-to-dictionary) — Mikhail Melnik, Jun 25 '15 at 11:29
thanks, I googled it, but I didn't find the same page. thanks for help — user87005, Jun 25 '15 at 11:38

score 7 · Answer 1 · answered Jun 25 '15 at 11:28

7

It's quite simple:

_to.update(_from)

answered Jun 25 '15 at 11:28

ElmoVanKielmo

10,907
2
32
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@user87005 - for use case 2 (which you have added after I posted my answer), it's not clear what should happen at the list level - if the list should be merged, updated (on which criteria). – ElmoVanKielmo Jun 26 '15 at 08:03

score 1 · Answer 2 · edited May 23 '17 at 11:43

1

There's a trap as below:

_to = {'host': 'test',
       'domain': [
           {
               'ssl': 0,
               'ssl_key': '',
           }
       ],
       'x': {}
       }
_from = {'status': 'on',
         'domain': [
             {
                 'ssl': 1,
                 'ssl_cert': 'nuyickK8uk4VxHissViL3O9dV7uGSLF62z52L4dAm78LeVdq'
             }
         ]
         }

_to['domain']['ssl_key'] omitted when _to.update(_from) If you wanna a deep update, check Update value of a nested dictionary of varying depth

edited May 23 '17 at 11:43

Community

1
1

answered Jun 25 '15 at 11:52

LittleQ

1,860
1
12
14

The desired output is in the question. – ElmoVanKielmo Jun 25 '15 at 11:53
looking into the post :) I have encountered same problem before @user87005 – LittleQ Jun 25 '15 at 12:24

how to merge two data structure in python

2 Answers2