Tuple grouping function. Useful for collapsing tabular data from left to right. Uses toolz; see http://toolz.readthedocs.org/en/latest/ See usage.txt below for examples.

group_tuples.py

from toolz.itertoolz.core import reduceby
from toolz.dicttoolz.core import valmap

def group_tuples(tuples):
    if len(tuples[0]) < 2:
        return [t[0] for t in tuples]
    result = reduceby(
        lambda t: t[0],
        lambda a, b: a + [b[1:]],
        tuples,
        []
    )
    with_counts = dict(
        ((k, len(v)), v) for (k, v) in result.items()
    )
    return valmap(group_tuples, with_counts)

usage.txt

Usage:
>>> tuples = [
  ('t1', 'c1', 'namex'),
  ('t1', 'c1', 'namey'),
  ('t2', 'c1', 'namey'),
  ('t1', 'c3', 'nameyt')
]

>>> group_tuples(tuples)
{('t1', 3): {('c1', 2): ['namex', 'namey'], ('c3', 1): ['nameyt']},
 ('t2', 1): {('c1', 1): ['namey']}}