Lexicographically sort deeply nested lists of mixed data types in Python 3 -

Lexicographically sort deeply nested lists of mixed data types in Python 3 -

in python 3, list.sort() method lexicographical sort. in python 3, comparing list float or int throws typeerror, unlike in python 2, can this:

>>> [0, 1] < 2 false

what best way accomplish old python 2 behavior?

i've tried subclassing list, work, each of nested lists must cast subclass type nested comparisons utilize overridden comparing methods. there way of accomplishing doesn't resort recursively converting each nested lists subclass?

i'd able compare 2 lists so:

>>> = [[[0, 1], [2, 3]], [0, 1]] >>> b = [[0, 1], [2, 3]] >>> < b false

the result should false because a[0][0] list , b[0][0] int, , in case ints should considered less list.

edit:

i'm looking implement sort function identical built-in python 3 list.sort, except when list beingness compared float or int, in case list should considered larger.

since, as mentioned in python 2 docs:

most other objects of built-in types compare unequal unless same object; selection whether 1 object considered smaller or larger 1 made arbitrarily consistently within 1 execution of program.

object comparing meaningful when 2 objects of same type. relying on value returned expressions such [0, 1] < 2 should not done in programme , that's why behaviour removed python 3.

to explain further, if have list [[[0, 1], [2, 3]], [0, 1]], has 2 elements: [[0, 1], [2, 3]] , [0, 1]. in order python sort them, compares internal values lexicographically, since both lists values [0, 1] , [2, 3] first 1 , 0 , 1 second. but, then, has compare [0, 1] 0, not of same type and, thus, comparing produces arbitrary results.

so, sorting broken.

having said above, if have lists can sorted meaningfully , cannot (because of above explanation), simple solution grab possible exception , homecoming false.

try: [0, 1] < 2 except typeerror: # homecoming or assign false. true not meaningful.

or, list.sort()

try: x.sort() except typeerror: pass # nothing. python produce meaningless results, anyway.

if want produce meaningful sorting (if makes sense), have define key function, mentioned. may rather complex, though. maybe looking @ problem different perspective better.

python list sorting python-3.x comparison