On 21/03/2019 17:06, Antoine Pitrou wrote:
On Fri, 22 Mar 2019 03:42:00 +1100 Steven D'Aprano firstname.lastname@example.org wrote:
For those who oppose the + operator, it will help me if you made it clear whether it is *just* the + symbol you dislike, and would accept the | operator instead, or whether you hate the whole operator concept regardless of how it is spelled.
I'd rather see a method. Dict merging just doesn't occur often enough that an operator is desirable for it.
Analogous to the relationship between list.sort() and sorted(), I can't help but think that a dict.merge() method would be a terrible idea. A merged() function is more defensible.
And to those who support this PEP, code examples where a dict merge operator will help are most welcome!
I don't use Python often enough to have much to offer, I'm afraid. The sort of occasion I would use dict merging is passing modified environments to subcommands. Something like:
def process(): if time_to_do_thing1(): thing1(base_env + thing1_env_stuff + env_tweaks) if time_to_do_thing2(): thing2(base_env + thing2_env_stuff + env_tweaks)
...and so on. The current syntax for doing this is a tad verbose:
def process(): if time_to_do_thing1(): env = base_env.copy() env.update(thing1_env_stuff) env.update(env_tweaks) thing1(env) del env if time_to_do_thing2(): env = base_env.copy() env.update(thing2_env_stuff) env.update(env_tweaks) thing2(env) del env