item_16.py

#!/usr/bin/env python3

# Copyright 2014 Brett Slatkin, Pearson Education 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.

# Preamble to mimick book environment
import logging
from pprint import pprint
from sys import stdout as STDOUT


# Example 1
def index_words(text):
    result = []
    if text:
        result.append(0)
    for index, letter in enumerate(text):
        if letter == ' ':
            result.append(index + 1)
    return result


# Example 2
address = 'Four score and seven years ago...'
address = 'Four score and seven years ago our fathers brought forth on this continent a new nation, conceived in liberty, and dedicated to the proposition that all men are created equal.'
result = index_words(address)
print(result[:3])


# Example 3
def index_words_iter(text):
    if text:
        yield 0
    for index, letter in enumerate(text):
        if letter == ' ':
            yield index + 1


# Example 4
result = list(index_words_iter(address))
print(result[:3])


# Example 5
def index_file(handle):
    offset = 0
    for line in handle:
        if line:
            yield offset
        for letter in line:
            offset += 1
            if letter == ' ':
                yield offset


# Example 6
address_lines = """Four score and seven years
ago our fathers brought forth on this
continent a new nation, conceived in liberty,
and dedicated to the proposition that all men
are created equal."""

with open('address.txt', 'w') as f:
    f.write(address_lines)

from itertools import islice
with open('address.txt', 'r') as f:
    it = index_file(f)
    results = islice(it, 0, 3)
    print(list(results))