total_sort.py

#
# Copyright 2011 Twitter, Inc.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
# 
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#

"""Simple word count example with reverse sorting of the words by frequency."""

from pycascading.helpers import *


def main():
    flow = Flow()
    input = flow.source(Hfs(TextLine(), 'pycascading_data/town.txt'))
    output = flow.tsv_sink('pycascading_data/out')

    @udf_map
    def split_words(tuple):
        for word in tuple.get(1).split():
            yield [word]

    input | \
    map_replace(split_words, 'word') | \
    group_by('word') | \
    native.count() | \
    group_by(Fields.VALUES, sort_fields=['count'], reverse_order=True) | \
    output

    flow.run(num_reducers=5)