Re: [Pyparsing] delimitedList Results

[Paul M. <pt...@au...>]

In place of:

ident   = p.Combine(name('id') + p.Optional(p.oneOf('- +')))

use:

ident   = p.Group(name('id') + p.Optional(p.oneOf('- +')))

The Group class is used to create sub-structures within a parsed result.
Otherwise, the default behavior for pyparsing is to just create a single
list of strings.

The reason you see all the id's in the internal directory for the
ParseResults is that it is possible to define a results name that is
actually an accumulator of all matching strings. When using the full call
syntax, add the listAllMatches argument, as in:

 expr.setResultsName("id", listAllMatches=True)

When using the abbreviated call syntax as you have done, use:

 expr("id*")

But based on what you have so far, I think Group is really the way to go. I
would also add a name for the optional trailing '+' or '-' sign, as in:

ident   = p.Group(name('id') + p.Optional(p.oneOf('- +')('sign')))

Then you can write:

for pt in r.points:
    if 'sign' in pt: # or "if pt.sign:"
        # do special sign stuff with pt.sign



-- Paul

-----Original Message-----
From: Loïc Berthe [mailto:lo...@li...] 
Sent: Wednesday, April 09, 2014 12:08 PM
To: pyp...@li...
Subject: [Pyparsing] delimitedList Results

	Hi,

I have some questions on how to use properly parseResults associated with a
delimitedList.

Here is the kind of line I would like to parse :

[code]
string = 'line 22 width=2;type=1 V101-,V103,V99+,V12 L102'
[/code]

And here is the parser I've built to extract information from this string:

[code]
import pyparsing as p


integer = p.Word(p.nums)
name    = p.Word(p.alphas, p.alphanums+'_')
ident   = p.Combine(name('id') + p.Optional(p.oneOf('- +')))

lineParser = (   'line'    + integer('num')
               + 'width='  + integer('width')+';'
               + 'type='   + integer('type')
               + p.delimitedList(ident)('points')
               + name('name')
                         )

r = lineParser.parseString(string)
[/code]

I can access to simple keys :

>>> print r.name
L102

but with delimitedList, it seems to be a bit more trickier as the associated
parseResults can not be used as a list of ParseResults but rather as a list
of
strings:

>>> for pt in r.points:
>>>     print type(pt), pt
   <type 'str'> V101-
   <type 'str'> V103
   <type 'str'> V99+
   <type 'str'> V12

I can get the list of point directly with r.points.asList(), but I don't
know how to access to the list of ids.

I was expecting that I could use classical __getitem__ method to list all
ids with something like [ pt.id for pt in r.points] Is there any way to do
this ?

Besides, I don't fully understand the structure of this parseResult :

>>> print repr(r.points)
(['V101-', 'V103', 'V99+', 'V12'], {'id': [('V101', 0), ('V103', 1), ('V99',
2), ('V12', 3)]})
 
it seems that the id key is associated with the list that I m looking for,
but when I try to retrieve it I only get one element of that list:

>>> r.points.id
V12

Have you got any clue?


Regards
--
Loïc

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