Features/refactor

README.md

@@ -10,7 +10,8 @@ A simple implementation of *Apriori algorithm* by Python.
 Features
 --------
 
-- Consisted of only one file and able to be used portably.
+- Is consisted of only one file and depends on no other libraries,
+  which enable you to use Apyori portably.
 - Can be used as APIs.
 - Supports a TSV output format for 2-items relations.
 

apyori.py

@@ -6,8 +6,10 @@
 
 import sys
 import argparse
+import json
 from collections import namedtuple
 from itertools import combinations
+from itertools import chain
 
 
 __version__ = '0.1.0'
@@ -38,21 +40,22 @@ def __init__(self, transactions):
         self.__num_transaction = 0
         self.__items = []
         self.__transaction_index_map = {}
-        self.add_transactions(transactions)
 
-    def add_transactions(self, transactions):
+        for transaction in transactions:
+            self.add_transaction(transaction)
+
+    def add_transaction(self, transaction):
         """
-        Add transactions.
+        Add a transaction.
 
-        @param  transactions    A transaction list.
+        @param  transaction A transaction.
         """
-        for transaction in transactions:
-            for item in transaction:
-                if item not in self.__transaction_index_map:
-                    self.__items.append(item)
-                    self.__transaction_index_map[item] = set()
-                self.__transaction_index_map[item].add(self.__num_transaction)
-            self.__num_transaction += 1
+        for item in transaction:
+            if item not in self.__transaction_index_map:
+                self.__items.append(item)
+                self.__transaction_index_map[item] = set()
+            self.__transaction_index_map[item].add(self.__num_transaction)
+        self.__num_transaction += 1
 
     def calc_support(self, items):
         """
@@ -146,7 +149,7 @@ def gen_support_records(
         max_length=None,
         _generate_candidates_func=create_next_candidates):
     """
-    Returns the supported relations.
+    Returns a generator of support records with given transactions.
     """
     candidates = transaction_manager.initial_candidates()
     length = 1
@@ -167,7 +170,7 @@ def gen_support_records(
 
 def gen_ordered_statistics(transaction_manager, record):
     """
-    Returns the relation stats.
+    Returns a generator of ordered statistics.
     """
     items = record.items
     combination_sets = [
@@ -192,15 +195,19 @@ def apriori(transactions, **kwargs):
     min_support = kwargs.get('min_support', 0.1)
     max_length = kwargs.get('max_length', None)
     min_confidence = kwargs.get('min_confidence', 0.0)
+    _gen_support_records = kwargs.get(
+        '_gen_support_records', gen_support_records)
+    _gen_ordered_statistics = kwargs.get(
+        '_gen_ordered_statistics', gen_ordered_statistics)
 
     # Calculate supports.
     transaction_manager = TransactionManager.create(transactions)
-    support_records = gen_support_records(
+    support_records = _gen_support_records(
         transaction_manager, min_support, max_length)
 
-    # Calculate stats.
+    # Calculate ordered stats.
     for support_record in support_records:
-        ordered_statistics = gen_ordered_statistics(
+        ordered_statistics = _gen_ordered_statistics(
             transaction_manager, support_record)
         filtered_ordered_statistics = [
             x for x in ordered_statistics if x.confidence >= min_confidence]
@@ -211,24 +218,31 @@ def apriori(transactions, **kwargs):
             filtered_ordered_statistics)
 
 
-def print_record_default(record, output_file):
+def dump_as_json(record, output_file):
     """
-    Print an Apriori algorithm result.
+    Dump an relation record as a json value.
 
     @param  record      A record.
     @param  output_file An output file.
     """
-    for ordered_stats in record.ordered_statistics:
-        output_file.write(
-            '{{{0}}} => {{{1}}} {2:.8f} {3:.8f} {4:.8f}\n'.format(
-                ','.join(ordered_stats.items_base),
-                ','.join(ordered_stats.items_add),
-                record.support, ordered_stats.confidence, ordered_stats.lift))
+    def default_func(value):
+        """
+        Default conversion for JSON value.
+        """
+        if isinstance(value, frozenset):
+            return sorted(value)
+        raise TypeError(repr(value) + " is not JSON serializable")
+
+    converted_record = record._replace(
+        ordered_statistics=[x._asdict() for x in record.ordered_statistics])
+    output_file.write(
+        json.dumps(converted_record._asdict(), default=default_func))
+    output_file.write('\n')
 
 
-def print_record_as_two_item_tsv(record, output_file):
+def dump_as_two_item_tsv(record, output_file):
     """
-    Print an Apriori algorithm result as two item TSV.
+    Dump a relation record as TSV only for 2 item relations.
 
     @param  record      A record.
     @param  output_file An output file.
@@ -238,57 +252,77 @@ def print_record_as_two_item_tsv(record, output_file):
             return
         if len(ordered_stats.items_add) != 1:
             return
-        output_file.write(
-            '{0}\t{1}\t{2:.8f}\t{3:.8f}\t{4:.8f}\n'.format(
-                [x for x in ordered_stats.items_base][0],
-                [x for x in ordered_stats.items_add][0],
-                record.support, ordered_stats.confidence, ordered_stats.lift))
+        output_file.write('{0}\t{1}\t{2:.8f}\t{3:.8f}\t{4:.8f}\n'.format(
+            list(ordered_stats.items_base)[0], list(ordered_stats.items_add)[0],
+            record.support, ordered_stats.confidence, ordered_stats.lift))
 
 
-def main():
+def parse_args(argv):
     """
-    Main.
+    Parse commandline arguments.
     """
+    output_funcs = {
+        'json': dump_as_json,
+        'tsv': dump_as_two_item_tsv,
+    }
+    default_output_func_key = 'json'
+
     parser = argparse.ArgumentParser()
     parser.add_argument(
-        '-i', '--input-file', help='Input file.', metavar='path',
-        type=argparse.FileType('r'), default=sys.stdin)
+        '-v', '--version', action='version',
+        version='%(prog)s {0}'.format(__version__))
+    parser.add_argument(
+        'input', metavar='inpath', nargs='*',
+        help='Input transaction file (default: stdin).',
+        type=argparse.FileType('r'), default=[sys.stdin])
     parser.add_argument(
-        '-o', '--output-file', help='Output file.', metavar='path',
+        '-o', '--output', metavar='outpath',
+        help='Output file (default: stdout).',
         type=argparse.FileType('w'), default=sys.stdout)
     parser.add_argument(
-        '-l', '--max-length', help='Max length.', metavar='int',
+        '-l', '--max-length', metavar='int',
+        help='Max length of relations (default: infinite).',
         type=int, default=None)
     parser.add_argument(
-        '-s', '--min-support', help='Minimum support (0.0-1.0).',
-        metavar='float', type=float, default=0.15)
+        '-s', '--min-support', metavar='float',
+        help='Minimum support ratio (must be > 0, default: 0.1).',
+        type=float, default=0.1)
     parser.add_argument(
-        '-c', '--min-confidence', help='Minimum confidence (0.0-1.0).',
-        metavar='float', type=float, default=0.6)
+        '-c', '--min-confidence', metavar='float',
+        help='Minimum confidence (default: 0.5).',
+        type=float, default=0.5)
     parser.add_argument(
-        '-d', '--delimiter', help='Delimiter for input.',
-        metavar='str', type=str, default='\t')
+        '-d', '--delimiter', metavar='str',
+        help='Delimiter for items of transactions (default: tab).',
+        type=str, default='\t')
     parser.add_argument(
         '-f', '--out-format', help='Output format (default or tsv).',
-        metavar='str', type=str, choices=['default', 'tsv'],
-        default='default')
-    args = parser.parse_args()
+        metavar='str', type=str, choices=output_funcs.keys(),
+        default=default_output_func_key)
+    args = parser.parse_args(argv)
+    if args.min_support <= 0:
+        raise ValueError('min support must be > 0')
+
+    args.output_func = output_funcs[args.out_format]
+    return args
+
+
+def main():
+    """
+    Main.
+    """
+    args = parse_args(sys.argv[1:])
 
     transactions = [
-        line.strip().split(args.delimiter)
-        for line in args.input_file]
+        line.strip().split(args.delimiter) for line in chain(*args.input)]
     result = apriori(
         transactions,
         max_length=args.max_length,
         min_support=args.min_support,
         min_confidence=args.min_confidence)
 
-    output_func = {
-        'default': print_record_default,
-        'tsv': print_record_as_two_item_tsv
-    }.get(args.out_format)
     for record in result:
-        output_func(record, args.output_file)
+        args.output_func(record, args.output)
 
 
 if __name__ == '__main__':

test/test_apriori.py

@@ -0,0 +1,83 @@
+"""
+Tests for apyori.apriori.
+"""
+
+from nose.tools import eq_
+from mock import Mock
+
+from apyori import TransactionManager
+from apyori import SupportRecord
+from apyori import RelationRecord
+from apyori import OrderedStatistic
+from apyori import apriori
+
+
+def test_empty():
+    """
+    Test for empty data.
+    """
+    transaction_manager = Mock(spec=TransactionManager)
+    def gen_support_records(*_):
+        """ Mock for apyori.gen_support_records. """
+        return iter([])
+
+    def gen_ordered_statistics(*_):
+        """ Mock for apyori.gen_ordered_statistics. """
+        yield OrderedStatistic(
+            frozenset(['A']), frozenset(['B']), 0.1, 0.7)
+
+    result = list(apriori(
+        transaction_manager,
+        _gen_support_records=gen_support_records,
+        _gen_ordered_statistics=gen_ordered_statistics,
+    ))
+    eq_(result, [])
+
+
+def test_normal():
+    """
+    Test for normal data.
+    """
+    transaction_manager = Mock(spec=TransactionManager)
+    min_support = 0.1
+    max_length = 2
+    support_record = SupportRecord(frozenset(['A', 'B']), 0.5)
+    ordered_statistic1 = OrderedStatistic(
+        frozenset(['A']), frozenset(['B']), 0.1, 0.7)
+    ordered_statistic2 = OrderedStatistic(
+        frozenset(['A']), frozenset(['B']), 0.3, 0.5)
+
+    def gen_support_records(*args):
+        """ Mock for apyori.gen_support_records. """
+        eq_(args[1], min_support)
+        eq_(args[2], max_length)
+        yield support_record
+
+    def gen_ordered_statistics(*_):
+        """ Mock for apyori.gen_ordered_statistics. """
+        yield ordered_statistic1
+        yield ordered_statistic2
+
+    # Will not create any records because of confidence.
+    result = list(apriori(
+        transaction_manager,
+        min_support=min_support,
+        min_confidence=0.4,
+        max_length=max_length,
+        _gen_support_records=gen_support_records,
+        _gen_ordered_statistics=gen_ordered_statistics,
+    ))
+    eq_(result, [])
+
+    # Will create a record.
+    result = list(apriori(
+        transaction_manager,
+        min_support=min_support,
+        min_confidence=0.3,
+        max_length=max_length,
+        _gen_support_records=gen_support_records,
+        _gen_ordered_statistics=gen_ordered_statistics,
+    ))
+    eq_(result, [RelationRecord(
+        support_record.items, support_record.support, [ordered_statistic2]
+    )])

test/test_dump_as_json.py

@@ -0,0 +1,58 @@
+"""
+Tests for apyori.dump_as_json.
+"""
+
+import json
+
+# For Python 2 compatibility.
+try:
+    from StringIO import StringIO
+except ImportError:
+    from io import StringIO
+
+from nose.tools import raises
+from nose.tools import eq_
+
+from apyori import RelationRecord
+from apyori import OrderedStatistic
+from apyori import dump_as_json
+
+
+def test_normal():
+    """
+    Test for normal data.
+    """
+    test_data = RelationRecord(
+        frozenset(['A']), 0.5,
+        [OrderedStatistic(frozenset([]), frozenset(['A']), 0.8, 1.2)]
+    )
+    output_file = StringIO()
+    dump_as_json(test_data, output_file)
+
+    output_file.seek(0)
+    result = json.loads(output_file.read())
+    eq_(result, {
+        'items': ['A'],
+        'support': 0.5,
+        'ordered_statistics': [
+            {
+                'items_base': [],
+                'items_add': ["A"],
+                'confidence': 0.8,
+                'lift': 1.2
+            }
+        ]
+    })
+
+
+@raises(TypeError)
+def test_bad():
+    """
+    Test for bad data.
+    """
+    test_data = RelationRecord(
+        set(['A']), 0.5,
+        [OrderedStatistic(frozenset([]), frozenset(['A']), 0.8, 1.2)]
+    )
+    output_file = StringIO()
+    dump_as_json(test_data, output_file)