[Python-ideas] Joining dicts again

[Chris Angelico]

On Mon, Feb 24, 2014 at 12:31 AM,  <haael at interia.pl> wrote:
> dict_default = {'a':None, 'b':[]}
> fun(**(funA(dict_default) | funB(dict_default))
>

All you need is a shorter name for your function and the job's done.
Since it'll be local to your module anyway, it doesn't need the long
and verbose name. Here's Steven's #3, implemented as a function:

def merge(a, b):
    "Merge two dicts using the 'or' operator
    c = a.copy()
    for key, value in b.items():
        if key in c:
            c[key] = c[key] or value
        else:
            c[key] = value

Or you could make it shorter thus:

def merge(a, b):
    "Merge two dicts using the 'or' operator
    c = a.copy()
    for key, value in b.items():
        c[key] = c.get(key) or value

Then your code is:

dict_default = {'a':None, 'b':[]}
fun(**merge(funA(dict_default), funB(dict_default)))

That's it!

ChrisA