def insert_into_conditional_fp_tree(self, pattern_list, count_of_pattern,
conditional_fp_tree,
conditional_header_table):
# return if patternArrayList is empty
if not pattern_list:
return
item_to_add_to_tree = pattern_list[0]
new_node = None
done = False
for child in conditional_fp_tree.children:
if child.item == item_to_add_to_tree:
new_node = child
child.count += count_of_pattern
done = True
break
if not done:
for header_pointer in conditional_header_table:
# remove non frequents too
if header_pointer.item == item_to_add_to_tree:
new_node = FPTree(item_to_add_to_tree)
new_node.count = count_of_pattern
new_node.parent = conditional_fp_tree
conditional_fp_tree.children.append(new_node)
while header_pointer.next is not None:
header_pointer = header_pointer.next
header_pointer.next = new_node
pattern_list.pop(0)
self.insert_into_conditional_fp_tree(pattern_list, count_of_pattern,
new_node,
conditional_header_table)
def insert_into_tree(self, transaction_sorted_by_frequency, fp_tree):
# return when list is empty
if not transaction_sorted_by_frequency:
return
item_to_add_to_tree = transaction_sorted_by_frequency[0]
new_node = None
done = False
for child in fp_tree.children:
if child.item == item_to_add_to_tree:
new_node = child
child.count += 1
done = True
break
if not done:
new_node = FPTree(item_to_add_to_tree)
new_node.count = 1
new_node.parent = fp_tree
fp_tree.children.append(new_node)
for header_pointer in self.header_table:
if header_pointer.item == item_to_add_to_tree:
while header_pointer.next is not None:
header_pointer = header_pointer.next
header_pointer.next = new_node
transaction_sorted_by_frequency.pop(0)
self.insert_into_tree(transaction_sorted_by_frequency, new_node)
def insert_into_conditional_fp_tree(self, pattern_list, count_of_pattern, conditional_fp_tree,
conditional_header_table):
# return if patternArrayList is empty
if not pattern_list:
return
item_to_add_to_tree = pattern_list[0]
new_node = None
done = False
for child in conditional_fp_tree.children:
if child.item == item_to_add_to_tree:
new_node = child
child.count += count_of_pattern
done = True
break
if not done:
for header_pointer in conditional_header_table:
# remove non frequents too
if header_pointer.item == item_to_add_to_tree:
new_node = FPTree(item_to_add_to_tree)
new_node.count = count_of_pattern
new_node.parent = conditional_fp_tree
conditional_fp_tree.children.append(new_node)
while header_pointer.next is not None:
header_pointer = header_pointer.next
header_pointer.next = new_node
pattern_list.pop(0)
self.insert_into_conditional_fp_tree(pattern_list, count_of_pattern, new_node, conditional_header_table)
def insert_into_tree(self, transaction_sorted_by_frequency, fp_tree):
# return when list is empty
if not transaction_sorted_by_frequency:
return
item_to_add_to_tree = transaction_sorted_by_frequency[0]
new_node = None
done = False
for child in fp_tree.children:
if child.item == item_to_add_to_tree:
new_node = child
child.count += 1
done = True
break
if not done:
new_node = FPTree(item_to_add_to_tree)
new_node.count = 1
new_node.parent = fp_tree
fp_tree.children.append(new_node)
for header_pointer in self.header_table:
if header_pointer.item == item_to_add_to_tree:
while header_pointer.next is not None:
header_pointer = header_pointer.next
header_pointer.next = new_node
transaction_sorted_by_frequency.pop(0)
self.insert_into_tree(transaction_sorted_by_frequency, new_node)
def fp_growth(self, base, threshold, header_table, frequent_patterns):
for item_in_tree in header_table:
current_pattern = (base if base is not None else "") + (
" " if base is not None else "") + item_in_tree.item
support_of_current_pattern = 0
conditional_pattern_base = dict()
while item_in_tree.next is not None:
item_in_tree = item_in_tree.next
support_of_current_pattern += item_in_tree.count
conditional_pattern = None
conditional_item = item_in_tree.parent
while not conditional_item.is_root():
conditional_pattern = conditional_item.item + " " + (
conditional_pattern
if conditional_pattern is not None else "")
conditional_item = conditional_item.parent
if conditional_pattern is not None:
conditional_pattern_base[
conditional_pattern] = item_in_tree.count
frequent_patterns[tuple(
current_pattern.split())] = support_of_current_pattern
# counting frequencies of single items in conditional pattern-base
conditional_items_map_to_frequency = dict()
for conditional_pattern in conditional_pattern_base:
split_conditional_pattern = conditional_pattern.split()
for item in split_conditional_pattern:
if item in conditional_items_map_to_frequency:
count = conditional_items_map_to_frequency[item]
count += conditional_pattern_base[conditional_pattern]
conditional_items_map_to_frequency[item] = count
else:
conditional_items_map_to_frequency[
item] = conditional_pattern_base[
conditional_pattern]
# create header table for conditional fp tree
conditional_header_table = []
for itemsForTable in conditional_items_map_to_frequency:
count = conditional_items_map_to_frequency[itemsForTable]
if count < threshold:
continue
f = FPTree(itemsForTable)
f.count = count
conditional_header_table.append(f)
conditional_fp_tree = self.build_conditional_fp_tree(
conditional_pattern_base, conditional_items_map_to_frequency,
threshold, conditional_header_table)
# header table with reverse ordering
conditional_header_table.sort(key=lambda x: x.count, reverse=True)
# children is not empty
if conditional_fp_tree.children:
self.fp_growth(current_pattern, threshold,
conditional_header_table, frequent_patterns)
def build_fp_tree(self, _input, items_map_to_frequencies,
sorted_items_by_frequencies, items_to_remove):
# build header table
# first element used as pointer
self.header_table = []
for itemsForTable in sorted_items_by_frequencies:
self.header_table.append(FPTree(itemsForTable))
self.fpTree = FPTree(None)
self.fpTree.root = True
transaction_sorted_by_frequency = []
with open(_input) as input_file:
for input_line in input_file:
token_list = re.split(r'[\s,\r\n]+', input_line)
# filter empty string
token_list = filter(None, token_list)
for item in token_list:
# ignore non-frequent items
if item in items_to_remove:
continue
index = 0
for string in transaction_sorted_by_frequency:
if items_map_to_frequencies[string] < items_map_to_frequencies[item] \
or (items_map_to_frequencies[string] == items_map_to_frequencies[item]
and string.lower() < item.lower()):
transaction_sorted_by_frequency.insert(index, item)
break
index += 1
if item not in transaction_sorted_by_frequency:
transaction_sorted_by_frequency.append(item)
# add to tree
self.insert_into_tree(transaction_sorted_by_frequency,
self.fpTree)
transaction_sorted_by_frequency.clear()
input_file.close()
# header table with reversing order
# first calculate the item frequencies in tree
for item in self.header_table:
count = 0
temp_item = item
while temp_item.next is not None:
temp_item = temp_item.next
count += temp_item.count
item.count = count
# sort header table
self.header_table.sort(key=lambda x: x.count, reverse=True)
def fp_growth(self, base, threshold, header_table, frequent_patterns):
for item_in_tree in header_table:
current_pattern = (base if base is not None else "") + (" " if base is not None else "") + item_in_tree.item
support_of_current_pattern = 0
conditional_pattern_base = dict()
while item_in_tree.next is not None:
item_in_tree = item_in_tree.next
support_of_current_pattern += item_in_tree.count
conditional_pattern = None
conditional_item = item_in_tree.parent
while not conditional_item.is_root():
conditional_pattern = conditional_item.item + " " + (
conditional_pattern if conditional_pattern is not None else "")
conditional_item = conditional_item.parent
if conditional_pattern is not None:
conditional_pattern_base[conditional_pattern] = item_in_tree.count
frequent_patterns[tuple(current_pattern.split())] = support_of_current_pattern
# counting frequencies of single items in conditional pattern-base
conditional_items_map_to_frequency = dict()
for conditional_pattern in conditional_pattern_base:
split_conditional_pattern = conditional_pattern.split()
for item in split_conditional_pattern:
if item in conditional_items_map_to_frequency:
count = conditional_items_map_to_frequency[item]
count += conditional_pattern_base[conditional_pattern]
conditional_items_map_to_frequency[item] = count
else:
conditional_items_map_to_frequency[item] = conditional_pattern_base[conditional_pattern]
# create header table for conditional fp tree
conditional_header_table = []
for itemsForTable in conditional_items_map_to_frequency:
count = conditional_items_map_to_frequency[itemsForTable]
if count < threshold:
continue
f = FPTree(itemsForTable)
f.count = count
conditional_header_table.append(f)
conditional_fp_tree = self.build_conditional_fp_tree(conditional_pattern_base,
conditional_items_map_to_frequency, threshold,
conditional_header_table)
# header table with reverse ordering
conditional_header_table.sort(key=lambda x: x.count, reverse=True)
# children is not empty
if conditional_fp_tree.children:
self.fp_growth(current_pattern, threshold, conditional_header_table, frequent_patterns)
def build_conditional_fp_tree(self, conditional_pattern_base, conditional_items_map_to_frequency, threshold,
conditional_header_table):
conditional_fp_tree = FPTree(None)
conditional_fp_tree.root = True
for pattern in conditional_pattern_base:
# removing non-frequent pattern and make a list instead of string
pattern_list = []
split_pattern = pattern.split()
for item in split_pattern:
if conditional_items_map_to_frequency[item] >= threshold:
pattern_list.append(item)
self.insert_into_conditional_fp_tree(pattern_list, conditional_pattern_base[pattern], conditional_fp_tree,
conditional_header_table)
return conditional_fp_tree
def build_conditional_fp_tree(self, conditional_pattern_base,
conditional_items_map_to_frequency,
threshold, conditional_header_table):
conditional_fp_tree = FPTree(None)
conditional_fp_tree.root = True
for pattern in conditional_pattern_base:
# removing non-frequent pattern and make a list instead of string
pattern_list = []
split_pattern = pattern.split()
for item in split_pattern:
if conditional_items_map_to_frequency[item] >= threshold:
pattern_list.append(item)
self.insert_into_conditional_fp_tree(
pattern_list, conditional_pattern_base[pattern],
conditional_fp_tree, conditional_header_table)
return conditional_fp_tree