blob: dc7cf32822de7e8acf58c727e9e0f7a429766e55 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
|
# (C) Copyright David Abrahams 2001. Permission to copy, use, modify, sell and
# distribute this software is granted provided this copyright notice appears in
# all copies. This software is provided "as is" without express or implied
# warranty, and with no claim as to its suitability for any purpose.
from utility import to_seq
def difference (b, a):
""" Returns the elements of B that are not in A.
"""
result = []
for element in b:
if not element in a:
result.append (element)
return result
def intersection (set1, set2):
""" Removes from set1 any items which don't appear in set2 and returns the result.
"""
result = []
for v in set1:
if v in set2:
result.append (v)
return result
def contains (small, large):
""" Returns true iff all elements of 'small' exist in 'large'.
"""
small = to_seq (small)
large = to_seq (large)
for s in small:
if not s in large:
return False
return True
def equal (a, b):
""" Returns True iff 'a' contains the same elements as 'b', irrespective of their order.
# TODO: Python 2.4 has a proper set class.
"""
return contains (a, b) and contains (b, a)
|
