Short circuting

Fri Jan 21 19:10:41 EST 2011

On 22.01.2011 00:33, Ed Connell wrote:
> Hi,
>> Consider the following please: (re_section, re_name, etc are
> previously compiled patterns)
>> result1 = re_section.search(line);
> result2 = re_name.search(line);
> result3 = re_data1.search(line);
> result4 = re_data2.search(line);
>> if result1:
> last_section = result1.group()[18:-5]
> elif result2:
> last_name = result2.group(0)[6:-1]
> elif result3:
> data[last_section] = {last_name:
> result3.group()[13:-5]}
> elif result4:
> data[last_section] = {last_name:
> result4.group()[17:-5]}
>> It gets my goat to have to obtain all resultx when I just want the
> first that is not None. (In theory, the number of results can be
> much longer.) I can think of alternatives (raising exceptions), but
> they all use deep indenting.
>> Ideas?
>> Ed
>
Maybe something like this (totally untested and probably wrong, I'm 
already quite tired):
for pattern in (re_section, re_name, re_data1, re_data2):
 result = pattern.search(line):
 if result:
 if pattern == re_section:
 last_section = result1.group()[18:-5]
 elif pattern == re_name:
 last_name = result2.group(0)[6:-1]
 elif pattern == re_data1:
 data[last_section] = {last_name: result3.group()[13:-5]}
 elif pattern == re_data2:
 data[last_section] = {last_name: result4.group()[17:-5]}
Also, if you have long if/elif ladders, look if you can apply the 
dictionary dispatch pattern.