[Tutor] Is there a better way to get a current mid-rate Yen quote with Python?
alan.gauld at btinternet.com
Sat Jul 26 01:11:50 CEST 2008
"Dick Moores" <rdm at rcblue.com> wrote
>>Certainly Beautiful Soup will not be muh longer and a lot more
>>elegant and probably more resilient.
> Alan, expand a bit, please. Longer? Resilient?
Longer as in lines of code. BS is good for extracting several
different parts from the soup, but just to pull out one very
specific item the setup and so on may mean that the
framework actually works out the same or longer than
Resilient as in able to handle unexpected changes in
the HTML used by the site or slight changes in formatting
of the results etc.
>>But to extract a single piece of text in a well defined location
>>then your approach although somewhat crude will work just fine.
> Crude? What's crude about my code?
Its just a little bit too hard coded for my liking, all that
splitting and searching means theres a lot of work going on
to extract a small piece of data. You iterate over the whole
page to do the first spliot, then you iterate over the whole
thing again to find the line you want. Consider thios line:
if 'JPY' in x and '>USDJPY=X<' in x:
Sincy JPY is in both strings the first check is effectively
redundant but still requires a string search over the line.
A well crafted regex would probably be faster than the
double in test and provide better checking by including
allowances for extra spaces or case changes etc.
Then having found the string once with 'in' you them have
to find it again with split(). You could just have done
a find the first time and stored the index as a basis for
the slicing later.
You also use lots of very specific slicing values to extract the
data - thats where you lose resilience compared to a parser
approach like BS. Again I suspect a regex might work better
in extracting the value. And hard coding the url in the function
also adds to its fragility.
Stylistically all those single character variable names hurts
readability and maintainability too.
> I want to improve, so please tell
It will work as is, but it could be tidied up a bit is all.
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