[Tutor] FW: files - strings - lists (fwd)

[Danny Yoo]

[Hi Paul; redirecting to tutor.  Try reposting to tutor next time; we may
need to see if there's some mailing list issue there.]


---------- Forwarded message ----------
Date: Thu, 1 Dec 2005 16:42:32 -0600
From: Paul McGuire <paul at alanweberassociates.com>
To: smiles at worksmail.net, dyoo at hkn.eecs.berkeley.edu
Subject: FW: [Tutor] files - strings - lists

(Sorry for the direct e-mail, tutor-list rejected my post. -- Paul)

-----Original Message-----
From: Paul McGuire [mailto:paul at alanweberassociates.com]
Sent: Thursday, December 01, 2005 11:07 AM
To: 'tutor at python.org'
Subject: [Tutor] files - strings - lists

Chris, Danny, et al. -

Sorry I didn't chime in earlier on this thread.  Here is a pyparsing sample
that goes beyond just tokenizing, and uses the structure of the input text
to organize the tokens into records with named attributes.

Enjoy!
-- Paul

# from earlier post
data = """1 Polonijna Liga Mistrzow
26 wrzesnia 2005
 6 12 6 4 1
 0 1 0
Bohossian - Kolinski
1
      1.000 9 13 19
      2.000 2 4 16
      1.000 10 8 17
      0.000 8 6 17
Szadkowska - Szczurek
2
      0.000 11 16 20
      3.000 1 -4 14
      3.500 3 -7 13
      2.500 10 13 19
"""

from pyparsing import *

real = Combine(Word(nums) + '.' + Word(nums)) integer =
Combine(Optional("-") + Word(nums))

# while we're parsing, might as well convert # integer strings to ints def
makeInt(st,loc,tokens): return int(tokens[0]) integer.setParseAction(
makeInt )

# we could get tricky and force names to start # only with capitals,
followed by all lower case, # but let's keep it simple name = Word(alphas)

# "26 wrzesnia 2005" looks suspiciously date-like date = integer + name +
integer

header = Group( integer + restOfLine + LineEnd() +
                date + LineEnd() +
                integer + integer + integer +
                    integer + integer + LineEnd() +
                integer + integer + integer )

dataline = Group(real +
                 integer.setResultsName("start") +
                 integer.setResultsName("end") +
                 integer + LineEnd() )

entry = Group( name.setResultsName("fromName") +
                    "-" +
                    name.setResultsName("toName") +
                    LineEnd() +
                integer.setResultsName("recnum") +
                    LineEnd() +
                OneOrMore( dataline ).setResultsName("data") )

# define the overal grammar definition
grammar = header.setResultsName("header") + \
    ZeroOrMore(entry).setResultsName("records")

# parse the input data string
results = grammar.parseString( data )

# print how many records found
print len(results.records)

# iterate over the returned records, and access # named data fields like
object attributes for rec in results.records:
    print rec.recnum, rec.fromName, "->", rec.toName
    for d in rec.data:
        print "-",d.start,d.end
    print

"""
Prints out:
2
1 Bohossian -> Kolinski
- 9 13
- 2 4
- 10 8
- 8 6

2 Szadkowska -> Szczurek
- 11 16
- 1 -4
- 3 -7
- 10 13
"""