A class that defines a compare function that can be used to sort lists of objects by any number of fields.
Python, 51 lines
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Copy to clipboard1 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 43 44 45 46 47 48 49 50 51 | class FieldCmp:
def __init__(self, fields, rev = 0):
self.fields = fields
if rev:
self.rev = -1
else:
self.rev = 1
def cmp(self, s1, s2):
for field in self.fields:
f1 = s1.__dict__[field]
f2 = s2.__dict__[field]
if f1 < f2:
return -1 * self.rev
elif f1 > f2:
return self.rev
return 0
if __name__ == '__main__':
class Struct:
def __init__(self, a, b, c):
self.a = a
self.b = b
self.c = c
def __repr__(self):
return repr((self.a, self.b, self.c))
l = [Struct(10, 20, 20), Struct(10, 10, 20), Struct(30, 20, 30)]
ll = l[:]
fc = FieldCmp(['a'])
ll.sort(fc.cmp)
print ll
ll = l[:]
fc = FieldCmp(['a'], 1)
ll.sort(fc.cmp)
print ll
ll = l[:]
fc = FieldCmp(['a', 'b'])
ll.sort(fc.cmp)
print ll
ll = l[:]
fc = FieldCmp(['a', 'b'], 1)
ll.sort(fc.cmp)
print ll
|
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