effectivepython/example_code/item_18.py at master · AISTLAB/effectivepython · GitHub

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#!/usr/bin/env python3

# 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 log(message, values):

if not values:

print(message)

else:

values_str = ', '.join(str(x) for x in values)

print('%s: %s' % (message, values_str))

log('My numbers are', [1, 2])

log('Hi there', [])

# Example 2

def log(message, *values): # The only difference

if not values:

print(message)

else:

values_str = ', '.join(str(x) for x in values)

print('%s: %s' % (message, values_str))

log('My numbers are', 1, 2)

log('Hi there') # Much better

# Example 3

favorites = [7, 33, 99]

log('Favorite colors', *favorites)

# Example 4

def my_generator():

for i in range(10):

yield i

def my_func(*args):

print(args)

it = my_generator()

my_func(*it)

# Example 5

def log(sequence, message, *values):

if not values:

print('%s: %s' % (sequence, message))

else:

values_str = ', '.join(str(x) for x in values)

print('%s: %s: %s' % (sequence, message, values_str))

log(1, 'Favorites', 7, 33) # New usage is OK

log('Favorite numbers', 7, 33) # Old usage breaks

effectivepython/example_code/item_18.py at master · AISTLAB/effectivepython · GitHub

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