The result that I need should be a real dict, not just a ChainMap. (It
is because I have to mutate it.)
d1 = {'a':1, 'b':2}
d2 = {'c':3, 'd':4}
d3 = {'e':5, 'f':6}
#1. My first naive approach was:
from collections import ChainMap
d = {}
for key,value in ChainMap(d1, d2, d3).items():
d[key] = value
#2. Much more effective version, but requires too many lines:
d= {}
d.update(d1)
d.update(d2)
d.update(d3)
#3. Third version is more compact. It uses a side effect inside a list
comp., so I don't like it either:
d = {}
[d.update(_) for _ in [d1, d2, d3]]
#4. Last version:
d = {}
d.update(ChainMap(d1, d2, d3))
Visually, it is the cleanest and the easiest to understand. However, it
uses ChainMap.__iter__ and that goes over all mappings in a loop written
in pure Python.
Is there a version that is as effective as #3, but as clean and nice as #4?
--
https://mail.python.org/mailman/listinfo/python-list
