模块

#!/usr/bin/python
# Filename: mymodule.py
def sayhi():
    print('Hi, this is mymodule speaking.')
__version__ = '0.1'
# 结束mymodule.py编写

#!/usr/bin/python
# Filename: mymodule_demo.py
import mymodule
mymodule.sayhi()
print ('Version', mymodule.__version__)

>>> import sys
>>> sys.path
['', '/usr/bin', '/usr/lib/python33.zip', '/usr/lib/python3.3
', '/usr/lib/python3.3/plat-linux', '/usr/lib/python3.3/lib-d
ynload', '/usr/lib/python3.3/site-packages', '/usr/lib/python
3.3/site-packages/setuptools-0.6c11.egg-info']

#!/usr/bin/python
# Filename: mymodule_demo2.py
from mymodule import sayhi, __version__
sayhi()
print('Version', __version__)Python en:Modules 59

from mymodule import *

#!/usr/bin/python
# Filename: using_name.py
if __name__ == '__main__':
    print('This program is being run by itself')
else:
    print('I am being imported from another module')

>>> import sys  # 得到sys模块的属性列表
>>> dir(sys)
['__displayhook__', '__doc__', '__excepthook__', '__loader__', '__name__', '__package__', '__stderr__', '__stdin__', '__stdout__', '_clear_type_cache', '_current_frames', '_debugmallocstats', '_getframe', '_home', '_mercurial', '_xoptions', 'abiflags', 'api_version', 'argv', 'base_exec_prefix', 'base_prefix', 'builtin_module_names', 'byteorder', 'call_tracing', 'callstats', 'copyright', 'displayhook', 'dont_write_bytecode', 'exc_info', 'excepthook', 'exec_prefix', 'executable', 'exit', 'flags', 'float_info', 'float_repr_style', 'getcheckinterval', 'getdefaultencoding', 'getdlopenflags', 'getfilesystemencoding', 'getprofile', 'getrecursionlimit', 'getrefcount', 'getsizeof', 'getswitchinterval', 'gettrace', 'hash_info', 'hexversion', 'implementation', 'int_info', 'intern', 'maxsize', 'maxunicode', 'meta_path', 'modules', 'path', 'path_hooks', 'path_importer_cache', 'platform', 'prefix', 'ps1', 'ps2', 'setcheckinterval', 'setdlopenflags', 'setprofile', 'setrecursionlimit', 'setswitchinterval', 'settrace', 'stderr', 'stdin', 'stdout', 'thread_info', 'version', 'version_info', 'warnoptions']
>>> del sys  # 删除sys模块
>>> dir(sys)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NameError: name 'sys' is not defined
>>> dir()  # 得到当前模块的属性列表
['__builtins__', '__doc__', '__loader__', '__name__', '__package__']
>>> a = 5 # create a new variable 'a'
>>> dir()
['__builtins__', '__doc__', '__name__', '__package__', 'a', 'sys']
>>> del a # 删除名字a
>>> dir()
['__builtins__', '__doc__', '__name__', '__package__', 'sys']

#!/usr/bin/python
# Filename: using_sys.py
import sys
print('The command line arguments are:')
for i in sys.argv: # 注意通过sys.argv引用
    print(i)
print('\n\nThe PYTHONPATH is', sys.path, '\n')

>>> import sys
>>> sys.version_info
(3, 0, 0, 'beta', 2)
>>> sys.version_info[0] >= 3
True

#!/usr/bin/python
# Filename: versioncheck.py
import sys, warnings
if sys.version_info[0] < 3:
    warnings.warn("Need Python 3.0 for this program to run",
        RuntimeWarning)
else:
    print('Proceed as normal')

>>> import os
>>> print(os.getcwd())
C:\Python31 
>>> os.chdir('/Users/pilgrim/diveintopython3/examples') # 即使在windows上也可以使用Linux风格的路径
>>> print(os.getcwd())
C:\Users\pilgrim\diveintopython3\examples

>>> import os 
>>> print(os.path.join('/Users/pilgrim/diveintopython3/examples/', 'humansize.py'))
/Users/pilgrim/diveintopython3/examples/humansize.py 
>>> print(os.path.join('/Users/pilgrim/diveintopython3/examples', 'humansize.py'))
/Users/pilgrim/diveintopython3/examples\humansize.py  # Windows下会添加一个反斜杠。*nix下则是正斜杠'/'
>>> print(os.path.expanduser('~')) 
c:\Users\pilgrim 
>>> print(os.path.join(os.path.expanduser('~'), 'diveintopython3', 'examples', 'humansize.py'))
c:\Users\pilgrim\diveintopython3\examples\humansize.py

>>> pathname = 
'/Users/pilgrim/diveintopython3/examples/humansize.py' 
>>> os.path.split(pathname) 
('/Users/pilgrim/diveintopython3/examples', 'humansize.py') 
>>> (dirname, filename) = os.path.split(pathname)  # 将多变量值传给一个元组
>>> dirname 
'/Users/pilgrim/diveintopython3/examples' 
>>> filename
'humansize.py' 
>>> (shortname, extension) = os.path.splitext(filename) 
5 
>>> shortname 
'humansize' 
>>> extension 
'.py'

>>> import os 
>>> print(os.getcwd()) 
c:\Users\pilgrim\diveintopython3\examples 
>>> metadata = os.stat('feed.xml')  # 调用 os.stat() 函数
>>> metadata.st_mtime   # 获取最后修改时间
1247520344.9537716
>>> import time # 用于在不同时间格式中转换
>>> time.localtime(metadata.st_mtime)
time.struct_time(tm_year=2009, tm_mon=7, tm_mday=13, 
tm_hour=17, 
tm_min=25, tm_sec=44, tm_wday=0, tm_yday=194, tm_isdst=1)
>>> metadata.st_size  # 返回文件大小
3070 
>>> import humansize 
>>> humansize.approximate_size(metadata.st_size)
'3.0 KiB'

>>> import os 
>>> print(os.getcwd()) 
c:\Users\pilgrim\diveintopython3\examples 
>>> print(os.path.realpath('feed.xml')) 
c:\Users\pilgrim\diveintopython3\examples\feed.xml

>>> os.chdir('/Users/pilgrim/diveintopython3/') 
>>> import glob 
>>> glob.glob('examples/*.xml')
['examples\\feed‐broken.xml', 
'examples\\feed‐ns0.xml', 
'examples\\feed.xml'] 
>>> os.chdir('examples/')
>>> glob.glob('*test*.py') 
['alphameticstest.py', 
'pluraltest1.py', 
'pluraltest2.py', 
'pluraltest3.py', 
'pluraltest4.py', 
'pluraltest5.py', 
'pluraltest6.py', 
'romantest1.py', 
'romantest10.py', 
'romantest2.py', 
'romantest3.py', 
'romantest4.py', 
'romantest5.py', 
'romantest6.py', 
'romantest7.py', 
'romantest8.py', 
'romantest9.py']

>>> s = '100 BROAD ROAD. APT 3'
>>> re.search(r'\bROAD\b',s)
<_sre.SRE_Match object at 0x7f0f85cb17e8>
>>> pattern = '^M{0,3}$' # 匹配0到3个'M'字符
>>> re.search(pattern, 'M') 
<_sre.SRE_Match object at 0x008EEB48> 
>>> re.search(pattern, 'MM') 
<_sre.SRE_Match object at 0x008EE090> 
>>> re.search(pattern, 'MMM') 
<_sre.SRE_Match object at 0x008EEDA8> 
>>> re.search(pattern, 'MMMM')
>>> re.findall('[0-9]+', '16 2-by-4s in rows of 8') # 找出字符串中出现该模式的所有地方
['16', '2', '4', '8']

>>> s = '100 BROAD ROAD. APT 3'
>>> mypattern = re.compile(r'\bROAD\b')
>>> mypattern.search(s)
<_sre.SRE_Match object at 0x7f141e9cb7e8>

>>> s = '100 BROAD ROAD. APT 3'
>>> re.sub(r'\bROAD\b', 'RD.', s)
'100 BROAD RD. APT 3'

>>> pattern = ''' 
    ^                   # beginning of string 
    M{0,3}              # thousands ‐ 0 to 3 Ms 
    (CM|CD|D?C{0,3})    # hundreds ‐ 900 (CM), 400 (CD), 0‐300 (0 to 3 Cs), 
                        # or 500‐800 (D, followed by 0 to 3 Cs) 
    (XC|XL|L?X{0,3})    # tens ‐ 90 (XC), 40 (XL), 0‐30 (0 to 3 Xs),
                        # or 50‐80 (L, followed by 0 to 3 Xs) 
    (IX|IV|V?I{0,3})    # ones ‐ 9 (IX), 4 (IV), 0‐3 (0 to 3 Is),
                        # or 5‐8 (V, followed by 0 to 3 Is) 
    $                   # end of string 
    ''' 
>>> re.search(pattern, 'M', re.VERBOSE)  # 注意必须传递 re.VERBOSE 参数
<_sre.SRE_Match object at 0x008EEB48> 
>>> re.search(pattern, 'MCMLXXXIX', re.VERBOSE)
<_sre.SRE_Match object at 0x008EEB48> 
>>> re.search(pattern, 'MMMDCCCLXXXVIII', re.VERBOSE)  
<_sre.SRE_Match object at 0x008EEB48> 
>>> re.search(pattern, 'M')

#!/usr/bin/python
# Filename: use_logging.py
import os, platform, logging
if platform.platform().startswith('Windows'):
    logging_file = os.path.join(os.getenv('HOMEDRIVE'),os.getenv('HOMEPATH'), 'test.log')
else:
    logging_file = os.path.join(os.getenv('HOME'), 'test.log')
logging.basicConfig(
    level=logging.DEBUG,
    format='%(asctime)s : %(levelname)s : %(message)s',
    filename = logging_file,
    filemode = 'w',
)
logging.debug("Start of the program")
logging.info("Doing something")
logging.warning("Dying now")

>>> import this
The Zen of Python, by Tim Peters
Beautiful is better than ugly.
Explicit is better than implicit.
Simple is better than complex.
Complex is better than complicated.
Flat is better than nested.
Sparse is better than dense.
Readability counts.
Special cases aren't special enough to break the rules.
Although practicality beats purity.
Errors should never pass silently.
Unless explicitly silenced.
In the face of ambiguity, refuse the temptation to guess.
There should be one-- and preferably only one --obvious way to do it.
Although that way may not be obvious at first unless you're Dutch.
Now is better than never.
Although never is often better than *right* now.
If the implementation is hard to explain, it's a bad idea.
If the implementation is easy to explain, it may be a good idea.
Namespaces are one honking great idea -- let's do more of those!