“预期字符串或缓冲区”

Question

我有这样的代码：

x=os.system("host www.google.com") 
b=re.findall(r'\w',x) 
print b 

但这返回以下错误：

TypeError: expected string or buffer 

Answer 1

从os.system的返回值是进程的退出代码。这是一个整数，而不是字符串，所以你基本上是这样做的：

>>> re.findall(r'\w', 0) 
Traceback (most recent call last): 
    File "<stdin>", line 1, in <module> 
    File "/usr/local/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/re.py", line 177, in findall 
    return _compile(pattern, flags).findall(string) 
TypeError: expected string or buffer 

我认为你正在寻找的功能是subprocess.check_output：

>>> import subprocess 
>>> print subprocess.check_output(['host', 'www.google.com']) 
www.google.com has address 173.194.75.147 
www.google.com has address 173.194.75.99 
www.google.com has address 173.194.75.103 
www.google.com has address 173.194.75.104 
www.google.com has address 173.194.75.105 
www.google.com has address 173.194.75.106 
www.google.com has IPv6 address 2607:f8b0:400c:c03::6a