def sam(sam_input, min_support=2):
'''Finds frequent item sets of items appearing in a list of transactions
based on the Split and Merge algorithm by Christian Borgelt.
:param sam_input: The input of the algorithm. Must come from
`get_sam_input`.
:param min_support: The minimal support of a set to be included.
:rtype: A set containing the frequent item sets and their support.
'''
fis = set()
report = {}
_sam(sam_input, fis, report, min_support)
return report
def sam(sam_input, min_support=2):
'''Finds frequent item sets of items appearing in a list of transactions
based on the Split and Merge algorithm by Christian Borgelt.
:param sam_input: The input of the algorithm. Must come from
`get_sam_input`.
:param min_support: The minimal support of a set to be included.
:rtype: A set containing the frequent item sets and their support.
'''
fis = set()
report = {}
_sam(sam_input, fis, report, min_support)
return report
def test_sam(should_print=False, ts=None, support=2):
if ts is None:
ts = get_default_transactions()
sam_input = get_sam_input(ts, lambda e: e)
fis = set()
report = {}
n = _sam(sam_input, fis, report, support)
if should_print:
print(n)
print(report)
return (n, report)
def test_sam(should_print=False, ts=None, support=2):
if ts is None:
ts = get_default_transactions()
sam_input = get_sam_input(ts, lambda e: e)
fis = set()
report = {}
n = _sam(sam_input, fis, report, support)
if should_print:
print(n)
print(report)
return (n, report)
def _sam(sam_input, fis, report, min_support):
n = 0
a = deque(sam_input)
while len(a) > 0 and len(a[0][1]) > 0:
b = deque()
s = 0
i = a[0][1][0]
while len(a) > 0 and len(a[0][1]) > 0 and a[0][1][0] == i:
s = s + a[0][0]
a[0] = (a[0][0], a[0][1][1:])
if len(a[0][1]) > 0:
b.append(a.popleft())
else:
a.popleft()
c = deque(b)
d = deque()
while len(a) > 0 and len(b) > 0:
if a[0][1] > b[0][1]:
d.append(b.popleft())
elif a[0][1] < b[0][1]:
d.append(a.popleft())
else:
b[0] = (b[0][0] + a[0][0], b[0][1])
d.append(b.popleft())
a.popleft()
while len(a) > 0:
d.append(a.popleft())
while len(b) > 0:
d.append(b.popleft())
a = d
if s >= min_support:
fis.add(i[1])
report[frozenset(fis)] = s
#print('{0} with support {1}'.format(fis, s))
n = n + 1 + _sam(c, fis, report, min_support)
fis.remove(i[1])
return n
def _sam(sam_input, fis, report, min_support):
n = 0
a = deque(sam_input)
while len(a) > 0 and len(a[0][1]) > 0:
b = deque()
s = 0
i = a[0][1][0]
while len(a) > 0 and len(a[0][1]) > 0 and a[0][1][0] == i:
s = s + a[0][0]
a[0] = (a[0][0], a[0][1][1:])
if len(a[0][1]) > 0:
b.append(a.popleft())
else:
a.popleft()
c = deque(b)
d = deque()
while len(a) > 0 and len(b) > 0:
if a[0][1] > b[0][1]:
d.append(b.popleft())
elif a[0][1] < b[0][1]:
d.append(a.popleft())
else:
b[0] = (b[0][0] + a[0][0], b[0][1])
d.append(b.popleft())
a.popleft()
while len(a) > 0:
d.append(a.popleft())
while len(b) > 0:
d.append(b.popleft())
a = d
if s >= min_support:
fis.add(i[1])
report[frozenset(fis)] = s
#print('{0} with support {1}'.format(fis, s))
n = n + 1 + _sam(c, fis, report, min_support)
fis.remove(i[1])
return n
