Comparing lists

[Francesco Bochicchio]

Hi all,

anybody can point me to a description of how the default comparison of
list objects (or other iterables) works?

Apparently l1 < l2 is equivalent to all ( x < y for x,y in
zip( l1, l2) ), has is shown in the following tests, but I can't find
it described anywhere:

[1,2,3] < [1,3,2] True
[1,2,3] < [1,2,4] True
[1,2,3] < [2,2,3] True
[1,2,3] < [0,1,3] False
[1,2,3] < [0,2,3] False
[1,2,3] < [1,1,3] False
[1,2,3] < [1,2,2]

False


Ciao

 

[Peter Otten]

Hi all,

anybody can point me to a description of how the default comparison of
list objects (or other iterables) works?

Apparently l1 < l2 is equivalent to all ( x < y for x,y in
zip( l1, l2) ), has is shown in the following tests, but I can't find
it described anywhere:

[1,2,3] < [1,3,2] True
[1,2,3] < [1,2,4] True
[1,2,3] < [2,2,3] True
[1,2,3] < [0,1,3] False
[1,2,3] < [0,2,3] False
[1,2,3] < [1,1,3] False
[1,2,3] < [1,2,2]

False


Ciao

Quoting http://docs.python.org/reference/expressions.html

"""
Tuples and lists are compared lexicographically using comparison of
corresponding elements. This means that to compare equal, each element must
compare equal and the two sequences must be of the same type and have the
same length.
If not equal, the sequences are ordered the same as their first differing
elements. For example, cmp([1,2,x], [1,2,y]) returns the same as cmp(x,y).
If the corresponding element does not exist, the shorter sequence is ordered
first (for example, [1,2] < [1,2,3]).
"""