Search in list of dictionaries
MRAB
google at mrabarnett.plus.com
Thu Feb 19 12:39:04 EST 2009
Alex Gusarov wrote:
> Hello everybody!
>
> I've a list of dictionaries with 'shorcut' and 'command' keys. When user
> types a word program must search this list for a typed shortcut and then
> run linked command. What I've wrote:
>
> for cmd in self.commands:
> if cmd['shortcut'] == input:
> os.popen(cmd['command'])
> break
> else:
> os.popen(input)
>
> But it's a brute-force method and I think there is another way in
> searching items through a list by dictionary key. Please give me advice
> how can I implement fast search in list of dictionaries by some
> dictionary key. In my mind language:
>
> list.get({'shortcut' == input})
>
If want to go from the shortcut to the command (cmd['shortcut'] ->
cmd['command']) the quickest way is using a dict, where cmd['shortcut']
is the key and cmd['command'] is the value:
self.command_dict = {}
for cmd in self.commands:
self.command_dict[cmd['shortcut']] = cmd['command']
and then:
os.popen(self.command_dict[input])
This will raise a KeyError if it's unknown. The equivalent of your code
above is:
os.popen(self.command_dict.get(input, input))
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