loop over list and process into groups

[nn]

lbolla wrote:
> On Mar 4, 3:57 pm, Sneaky Wombat <joe.hr... at gmail.com> wrote:
> > [ {'vlan_or_intf': 'VLAN2021'},
> >  {'vlan_or_intf': 'Interface'},
> >  {'vlan_or_intf': 'Po1'},
> >  {'vlan_or_intf': 'Po306'},
> >  {'vlan_or_intf': 'VLAN2022'},
> >  {'vlan_or_intf': 'Interface'},
> >  {'vlan_or_intf': 'Gi7/33'},
> >  {'vlan_or_intf': 'Po1'},
> >  {'vlan_or_intf': 'Po306'},
> >  {'vlan_or_intf': 'VLAN2051'},
> >  {'vlan_or_intf': 'Interface'},
> >  {'vlan_or_intf': 'Gi9/6'},
> >  {'vlan_or_intf': 'VLAN2052'},
> >  {'vlan_or_intf': 'Interface'},
> >  {'vlan_or_intf': 'Gi9/6'},]
> >
> > I want it to be converted to:
> >
> > [{'2021':['Po1','Po306']},{'2022':['Gi7/33','Po1','Po306']},etc etc]
> >
> > I was going to write a def to loop through and look for certain pre-
> > compiled regexs, and then put them in a new dictionary and append to a
> > list, but I'm having trouble thinking of a good way to capture each
> > dictionary.  Each dictionary will have a key that is the vlan and the
> > value will be a list of interfaces that participate in that vlan.
> > Each list will be variable, many containing only one interface and
> > some containing many interfaces.
> >
> > I thought about using itertools, but i only use that for fixed data.
> > I don't know of a good way to loop over variably sized data.  I was
> > wondering if anyone had any ideas about a good way to convert this
> > list or dictionary into the right format that I need.  The solution I
> > come up with will most likely be ugly and error prone, so I thought
> > i'd ask this python list while I work.  Hopefully I learn a better way
> > to solve this problem.
> >
> > Thanks!
> >
> > I also have the data in a list,
> >
> > [ 'VLAN4065',
> >  'Interface',
> >  'Gi9/6',
> >  'Po2',
> >  'Po3',
> >  'Po306',
> >  'VLAN4068',
> >  'Interface',
> >  'Gi9/6',
> >  'VLAN4069',
> >  'Interface',
> >  'Gi9/6',]
>
>
>
> ===================================
>
> from itertools import groupby
>
> data = \
> [ {'vlan_or_intf': 'VLAN2021'},
>  {'vlan_or_intf': 'Interface'},
>  {'vlan_or_intf': 'Po1'},
>  {'vlan_or_intf': 'Po306'},
>  {'vlan_or_intf': 'VLAN2022'},
>  {'vlan_or_intf': 'Interface'},
>  {'vlan_or_intf': 'Gi7/33'},
>  {'vlan_or_intf': 'Po1'},
>  {'vlan_or_intf': 'Po306'},
>  {'vlan_or_intf': 'VLAN2051'},
>  {'vlan_or_intf': 'Interface'},
>  {'vlan_or_intf': 'Gi9/6'},
>  {'vlan_or_intf': 'VLAN2052'},
>  {'vlan_or_intf': 'Interface'},
>  {'vlan_or_intf': 'Gi9/6'},]
>
> def clean_up(lst):
> 	return [d.values()[0] for d in data if d.values()[0] != 'Interface']
>
> out = {}
> for k, g in groupby(clean_up(data) , key=lambda s:
> s.startswith('VLAN')):
> 	if k:
> 		key = list(g)[0].replace('VLAN','')
> 	else:
> 		out[key] = list(g)
>
> print out
> ===================================
>
> hth,
> L.

Good use of groupby. Here is what I ended up coming up:

from itertools import groupby
laninfo=[ 'VLAN4065',
 'Interface',
 'Gi9/6',
 'Po2',
 'Po3',
 'Po306',
 'VLAN4068',
 'Interface',
 'Gi9/6',
 'VLAN4069',
 'Interface',
 'Gi9/6',]

def splitgrp(s, f=[False]):
   f[0]^=s.startswith('VLAN')
   return f[0]
lanlst=(list(g) for k,g in groupby(laninfo,key=splitgrp))
out={item[0][4:]:item[2:] for item in lanlst}
print(out)