# 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
import random
with open('my_file.txt', 'w') as f:
for _ in range(10):
f.write('a' * random.randint(0, 100))
f.write('\n')
value = [len(x) for x in open('my_file.txt')]
print(value)
[94, 48, 19, 7, 27, 36, 92, 33, 25, 9]
# Example 2
it = (len(x) for x in open('my_file.txt'))
print(it)
<generator object <genexpr> at 0x103e45e08>
### It returns iterator.
# Example 3
print(next(it))
print(next(it))
94 48
# Example 4
roots = ((x, x**0.5) for x in it)
print(roots)
<generator object <genexpr> at 0x103e45eb8>
# Example 5
print(next(roots))
(19, 4.358898943540674)