python转置除第一列之外的列表列表

Question

we can transpose list of list using

map(list, zip(*l))

Can we change some thing in the above command to transpose the following list of lists, except the first element of inner list ?

l = [["item1",1,2,3],["item2",4,5,6],["item3",7,8,9]]

The result I'm looking for is

r = [["item1",1,4,7],["item2",2,5,8],["item3",3,6,9]]

Answer 1

Alternative solution:

In [2]: it = [iter(x) for x in l]

In [3]: [list(x) for x in zip([next(x) for x in it], *it)]
Out[3]: [['item1', 1, 4, 7], ['item2', 2, 5, 8], ['item3', 3, 6, 9]]

First, this builds a list of iterators over sublists of l ( it ).

[next(x) for x in it] advances each iterator in it and collects the results (first elements of lists) into a list, which is then zip ped together with previously incremented iterators from it .

Answer 2

There are easier ways if say you want to use pandas...

headers = [item[0] for item in l]
data = [item[1:] for item in l]
r = map(list, zip(*data))
for i, item in enumerate(r):
    item.insert(0, headers[i])