Re: Parsing a search string

[Freddie]

Reinhold Birkenfeld wrote:
Freddie wrote:
Happy new year! Since I have run out of alcohol, I'll ask a question that I 
haven't really worked out an answer for yet. Is there an elegant way to turn 
something like:

> moo cow "farmer john" -zug
into:
['moo', 'cow', 'farmer john'], ['zug']
I'm trying to parse a search string so I can use it for SQL WHERE constraints, 
preferably without horrifying regular expressions. Uhh yeah.

The shlex approach, finished:
searchstring = 'moo cow "farmer john" -zug'
lexer = shlex.shlex(searchstring)
lexer.wordchars += '-'
poslist, neglist = [], []
while 1:
    token = lexer.get_token()
    # token is '' on eof
    if not token: break
    # remove quotes
    if token[0] in '"\'':
        token = token[1:-1]
    # select in which list to put it
    if token[0] == '-':
        neglist.append(token[1:])
    else:
        poslist.append(token)
regards,
Reinhold
Thanks for this, though there was one issue:
>>> lexer = shlex.shlex('moo cow +"farmer john" -dog')
>>> lexer.wordchars += '-+'
>>> while 1:
...     tok = lexer.get_token()
...     if not tok: break
...     print tok
...
moo
cow
+"farmer
john"
-dog
The '+"farmer john"' part would be turned into two seperate words, '+"farmer' 
and 'john"'. I ended up using shlex.split() (which the docs say is new in 
Python 2.3), which gives me the desired result. Thanks for the help from 
yourself and M.E.Farmer :)

Freddie
>>> shlex.split('moo cow +"farmer john" -"evil dog"')
['moo', 'cow', '+farmer john', '-evil dog']
>>> shlex.split('moo cow +"farmer john" -"evil dog" +elephant')
['moo', 'cow', '+farmer john', '-evil dog', '+elephant']
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