Python| os.path.commonpath() 方法

Python中的OS 模块提供了与操作系统交互的功能。操作系统属于 Python 的标准实用程序模块。该模块提供了一种使用操作系统相关功能的可移植方式。 os.path模块是Python中OS 模块的子模块，用于常见的路径名操作。

Python中的os.path.commonpath()方法用于获取路径列表中最长的公共子路径。如果指定的路径列表包含绝对路径和相对路径，或者为空，则此方法引发ValueError 。与os.path.commonpath()方法不同，返回值是有效路径。
例如，考虑以下路径列表：

list of paths                     Longest common sub-path
['/home/User/Photos', /home/User/Videos']        /home/User          
['/usr/local/bin', '/usr/lib']                   /usr               

Syntax: os.path.commonpath(list)

Parameter:
path: A list of path-like object. A path-like object is either a string or bytes object representing a path.

Return Type: This method returns a string value which represents the longest common sub-path in the specified list.

代码 #1：使用 os.path.commonpath() 方法

# Python program to explain os.path.commonpath() method 
    
# importing os module 
import os
  
# List of Paths
paths = ['/home/User/Desktop', '/home/User/Documents', 
         '/home/User/Downloads'] 
  
# Get the
# longest common sub-path
# in the specified list 
prefix = os.path.commonpath(paths)
  
  
# Print the 
# longest common sub-path
# in the specified list 
print("Longest common sub-path:", prefix)
  
  
# List of Paths
paths = ['/usr/local/bin', '/usr/bin'] 
  
# Get the
# longest common sub-path
# in the specified list 
prefix = os.path.commonpath(paths)
  
  
# Print the 
# longest common sub-path
# in the specified list 
print("Longest common sub-path:", prefix)

输出：

Longest common sub-path: /home/User
Longest common sub-path: /usr

代码 #2：使用 os.path.commonpath() 方法

# Python program to explain os.path.commonpath() method 
    
# importing os module 
import os
  
# List of Paths
paths = ['/usr/local/bin', 'usr/bin'] 
  
# Get the
# longest common sub-path
# in the specified list 
prefix = os.path.commonpath(paths)
  
  
# Print the 
# longest common sub-path
# in the specified list 
print("Longest common sub-path:", prefix)
  
  
# The above code will raise
# ValueError as list of paths
# contains both absolute and
# relative path

输出：

Traceback (most recent call last):
  File "oscommonpath.py", line 12, in 
    prefix = os.path.commonpath(paths)
  File "/usr/lib/python3.6/posixpath.py", line 505, in commonpath
    raise ValueError("Can't mix absolute and relative paths") from None
ValueError: Can't mix absolute and relative paths

注意：如果指定的列表为空， os.path.commonpath()方法也会引发ValueError 。

参考： https://docs。 Python.org/3/library/os.path.html