find isset() php function equivalent in python

[Ola Natvig]

Max M wrote:
> Ola Natvig wrote:
> 
>> Olivier Noblanc ATOUSOFT wrote:
>>
>>> Hello
>>>
>>>
>>> What is the equivalent function of php isset() in python
>>
>>
>> try:
>>     if variable:
>>         # isset
>>         pass
>> except NameError:
>>     # not set
>>     pass
>>     
> 
> 
> you could use:
> 
>  >>> 'variable' in vars()
> 
> But be aware that it is bad bad practice to do it like that.
> 
> If you need variables that you don't know that name of, you should put 
> them in a dictionary. They are made for that exact purpose.
> 
>  >>> unkown_vars = {}
>  >>> unkown_vars['variable'] = 42
>  >>> 'variable' in unkown_vars
> True
> 
> 

If it's a greater possibility that the 'variable' are set than it's not 
you will get better performance when using:

try:
	print unknown_vars['variable']
except KeyError:
	print 'variable are not set'

istead of

if 'variable' in unknown_vars:
	print unknown_vars['variable']
else:
	print 'variable are not set'

You could even use

print unknown_vars.get('variable', 'variable are not set')

dictionary.get(key, default) returns the default if key are not located 
in the dictionary, I'm not sure if the function uses the try / except 
KeyError aproach or what it uses.

-- 
--------------------------------------
  Ola Natvig <ola.natvig at infosense.no>
  infoSense AS / development