CODEWITHSUNDEEP
pythonpython-2.7
corvid
corvid

Reputation: 11197

returning a dict-like structure from a groupby

here is the basic code:

from my_parser import data
from itertools import groupby
from collections import Counter

def grades(date=datetime.now().strftime('%Y%m')):
  this_month = self.data.key_by('GRADE').pop(date) # this gives a list of this month
  monthly = dict(groupby(this_month, lambda k: make_letter(k.GRADE))) # group it by letter grade
  c = [{
    'month': k,
    'total': len(x)
  } for k,x in monthly.iteritems()]

however, the dictionary returns like so:

A : <itertools._grouper object at 0x1033f0c90>
C : <itertools._grouper object at 0x1033f0c50>

is it possible to get it to return more like this, or an alternate tool to do the same concept?

{
  A : [ ... ]
  B : [ ... ]
}

Upvotes: 2

Views: 59

Answers (1)

Hugh Bothwell
Hugh Bothwell

Reputation: 56674

Instead of

monthly = dict(groupby(this_month, lambda k: make_letter(k.GRADE))) # group it by letter grade

try

monthly = {
    val:list(items)
    for val,items in
    groupby(this_month, lambda k: make_letter(k.GRADE))
}

Edit: You may need to pre-sort this_month such that grades are in ascending order (or at least such that all grades corresponding to a given letter appear together).

Upvotes: 2

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