Snowman08 Snowman08 - 3 months ago 8
Python Question

Partition list based on elements of another list as keys

How can I combine these two lists and use

alist
as keys and
blist
as values? What I would like to do is group the values in
blist
with the corresponding keys. So let's say values
3, 4, 2, None, None, 1, 1, 1, 6, 1, 2, 4, 5, 5, 7, 1, 1, 2, 3, 4, 5
should have
'Inner OD'
as key and the remaining should have a key
'Outter OD'
:
None, 3, 4, 6, 5, 1, 3, 2, 2, 2, 2, 1, 1, 1, 1, 3, 4, 3, 5, 6, 5, 2, 3


so basically I would want it to look like this

{'Inner OD': [3, 4, 2, None, None, 1, 1, 1, 6, 1, 2, 4, 5, 5, 7, 1, 1, 2, 3, 4, 5], 'Outter OD': [None, 3, 4, 6, 5, 1, 3, 2, 2, 2, 2, 1, 1, 1, 1, 3, 4, 3, 5, 6, 5, 2, 3]})


Any help would be greatly appreciated.

alist = [u'Outter OD', u'Outter OD', u'Inner OD', u'Inner OD', u'Inner OD', u'Inner OD', u'Inner OD', u'Inner OD', u'Inner OD', u'Inner OD', u'Inner OD', u'Inner OD', u'Inner OD', u'Inner OD', u'Inner OD', u'Inner OD', u'Inner OD', u'Inner OD', u'Inner OD', u'Inner OD', u'Inner OD', u'Inner OD', u'Inner OD', u'Inner OD', u'Inner OD', u'Inner OD', u'Outter OD', u'Outter OD', u'Outter OD', u'Outter OD', u'Outter OD', u'Outter OD', u'Outter OD', u'Outter OD', u'Outter OD', u'Outter OD', u'Outter OD', u'Outter OD', u'Outter OD', u'Outter OD', u'Outter OD', u'Outter OD', u'Outter OD', u'Outter OD', u'Outter OD']

blist = [3, 4, 2, None, None, 1, 1, 1, 6, 1, 2, 4, 5, 5, 7, 1, 1, 2, 3, 4, 5, 1, None, 3, 4, 6, 5, 1, 3, 2, 2, 2, 2, 1, 1, 1, 1, 3, 4, 3, 5, 6, 5, 2, 3]

Answer

Something like this:

res = {}
for i in range(len(alist)):
    if alist[i] in res:
        res[alist[i]].append(blist[i])
    else:
        res[alist[i]]=[blist[i]]

returns {'Inner OD': [2, None, None, 1, 1, 1, 6, 1, 2, 4, 5, 5, 7, 1, 1, 2, 3, 4, 5, 1, None, 3, 4, 6], 'Outter OD': [3, 4, 5, 1, 3, 2, 2, 2, 2, 1, 1, 1, 1, 3, 4, 3, 5, 6, 5, 2, 3]}