Python, merge multi-level dictionaries
dictionary, python
Solution
import collections # requires Python 2.7 -- see note below if you're using an earlier version
def merge_dict(d1, d2):
"""
Modifies d1 in-place to contain values from d2. If any value
in d1 is a dictionary (or dict-like), *and* the corresponding
value in d2 is also a dictionary, then merge them in-place.
"""
for k,v2 in d2.items():
v1 = d1.get(k) # returns None if v1 has no value for this key
if ( isinstance(v1, collections.Mapping) and
isinstance(v2, collections.Mapping) ):
merge_dict(v1, v2)
else:
d1[k] = v2
If you're not using Python 2.7+, then replace `isinstance(v, collections.Mapping)` with `isinstance(v, dict)` (for strict typing) or `hasattr(v, "items")` (for duck typing).
Note that if there's a conflict for some key -- i.e., if d1 has a string value and d2 has a dict value for that key -- then this implementation just keeps the value from d2 (similar to `update`)
Problem
Possible Duplicate: python: Dictionaries of dictionaries merge ``` my_dict= {'a':1, 'b':{'x':8,'y':9}} other_dict= {'c':17,'b':{'z':10}} my_dict.update(other_dict) ``` results in: ``` {'a': 1, 'c': 17, 'b': {'z': 10}} ``` but i want this: ``` {'a': 1, 'c': 17, 'b': {'x':8,'y':9,'z': 10}} ``` How can i do this? (possibly in a simple way?)