# 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 to_str(bytes_or_str):
if isinstance(bytes_or_str, bytes):
value = bytes_or_str.decode('utf-8')
else:
value = bytes_or_str
return value # Instance of str
print(repr(to_str(b'foo')))
print(repr(to_str('foo')))
'foo' 'foo'
# Example 2
def to_bytes(bytes_or_str):
if isinstance(bytes_or_str, str):
value = bytes_or_str.encode('utf-8')
else:
value = bytes_or_str
return value # Instance of bytes
print(repr(to_bytes(b'foo')))
print(repr(to_bytes('foo')))
b'foo' b'foo'
# Example 3
# Python 2
def to_unicode(unicode_or_str):
if isinstance(unicode_or_str, str):
value = unicode_or_str.decode('utf-8')
else:
value = unicode_or_str
return value # Instance of unicode
print(repr(to_unicode(u'foo')))
print(repr(to_unicode('foo')))
--------------------------------------------------------------------------- AttributeError Traceback (most recent call last) <ipython-input-12-4e3c5d02321f> in <module>() 8 return value # Instance of unicode 9 ---> 10 print(repr(to_unicode(u'foo'))) 11 print(repr(to_unicode('foo'))) <ipython-input-12-4e3c5d02321f> in to_unicode(unicode_or_str) 3 def to_unicode(unicode_or_str): 4 if isinstance(unicode_or_str, str): ----> 5 value = unicode_or_str.decode('utf-8') 6 else: 7 value = unicode_or_str AttributeError: 'str' object has no attribute 'decode'
# Example 4
# Python 2
def to_str(unicode_or_str):
if isinstance(unicode_or_str, unicode):
value = unicode_or_str.encode('utf-8')
else:
value = unicode_or_str
return value # Instance of str
print(repr(to_str(u'foo')))
print(repr(to_str('foo')))
Need to write binary mode ('wb')
# Example 5
try:
import os
with open('random.bin', 'w') as f:
f.write(os.urandom(10))
except:
logging.exception('Expected')
else:
assert False
# Example 6
with open('random.bin', 'wb') as f:
f.write(os.urandom(10))