Short circuting

Fri Jan 21 23:19:30 EST 2011

On 1/21/11 5:33 PM, 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.

parsers = [
 ('section', re_section, lambda r: r.group()[18:-5]),
 ('name', re_name, lambda r: r.group()[6:-1]),
 ('data1', re_data1, lambda r: r.group()[13:-5]),
 ('data2', re_data2, lambda r: r.group()[17:-5]),
]
data = {}
for line in lines:
 values = {}
 for key, regex, extract in parsers:
 m = regex.search(line)
 if m is not None:
 values[key] = extract(m)
 break
 if 'data1' in values:
 data[values['section']] = {values['name']: values['data1']}
 elif 'data2' in values:
 data[values['section']] = {values['name']: values['data2']}
-- 
Robert Kern
"I have come to believe that the whole world is an enigma, a harmless enigma
 that is made terrible by our own mad attempt to interpret it as though it had
 an underlying truth."
 -- Umberto Eco