Pythonic way to split a list into first and rest?

Python Programming

Question or problem about Python programming:

I think in Python 3 I’ll be able to do:

first, *rest = l

which is exactly what I want, but I’m using 2.6. For now I’m doing:

first = l[0]
rest = l[1:]

This is fine, but I was just wondering if there’s something more elegant.

How to solve the problem:

Solution 1:

first, rest = l[0], l[1:]

Basically the same, except that it’s a oneliner. Tuple assigment rocks.

This is a bit longer and less obvious, but generalized for all iterables (instead of being restricted to sliceables):

i = iter(l)
first = next(i) # in older versions
rest = list(i)

Solution 2:

You can do

first = l.pop(0)

and then l will be the rest. It modifies your original list, though, so maybe it’s not what you want.

Solution 3:

Yet another one, working with python 2.7. Just use an intermediate function. Logical as the new behavior mimics what happened for functions parameters passing.

li = [1, 2, 3]
first, rest = (lambda x, *y: (x, y))(*li)

Solution 4:

I would suggest:

first, remainder = l.split(None, maxsplit=1)

Hope this helps!