Re: Search in list of dictionaries

[MRAB]

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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Re: Search in list of dictionaries

[Alex Gusarov]

Thanks! This example is quite simple and works exactly the way I wanted.

On Thu, Feb 19, 2009 at 11:39 PM, MRAB goo...@mrabarnett.plus.com wrote:

 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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 http://mail.python.org/mailman/listinfo/python-list

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