[Tutor] quick speed question

[Dave Angel]

On 2:59 PM, C.T. Matsumoto wrote:
> Hello Tutors,
>
> I was just wondering if you have a dictionary key is it faster to do:
>
> if dict['key'] == 'foo':
>     ...
>
> or is this faster:
>
> if 'foo' in dict['key']:
>     ...
>
> Or is there any difference and I'm chasing ghosts?
>
> Thanks,
>
> T
dict is not a good name for a dictionary, since it's a built-in name.  
But ignoring that,

The two lines you show do different things

Both of them look up a single item in the dictionary, so that part takes 
the same time.  But then the first compares the resulting string to 
exactly 'foo', while the second searches in the string to see if 'foo' 
is a substring.

If you need one of them, the other will get the wrong answer.  So 
knowing that the first is faster is irrelevant.

DaveA