Python| os.path.expanduser() 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.expanduser()方法用于将给定路径中的初始路径组件~ （波浪号）或 ~user 扩展到用户的主目录。
在 Unix 平台上，如果设置了HOME环境变量的值，则初始~将被替换。否则， os.path.expanduser()方法使用内置模块pwd在密码目录中搜索用户的主目录。直接在密码目录中查找包含初始~user组件的路径。
在 Windows 平台上，初始的~被HOME和USERPROFILE环境变量的值替换（如果已设置）。否则，将使用HOMEPATH和HOMEDRIVE环境变量。而包含初始~user组件的路径是通过将最后一个目录组件替换为上面派生的路径中的~ user 来处理的。

Syntax: os.path.expanduser(path)
Parameter: 
path: A path-like object representing a file system path. 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 path after expanding an initial path component ~ or ~user in the given path.
 

代码 #1：使用 os.path.expanduser() 方法（在 Unix 上）

Python3

# Python program to explain os.path.expanduser() method 
    
# importing os.path module 
import os.path
  
  
# Path
path = "~/file.txt"
  
# Expand an initial ~ component
# in the given path
# using os.path.expanduser() method
full_path = os.path.expanduser(path)
  
# print the path after
# expanding the initial ~ component
# in the given path
print(full_path)
  
  
# Change the value of
# HOME environment variable
os.environ["HOME"] = "/home / GeeksForGeeks"
  
  
# Now, Expand the initial ~ component
# in the same path
# using os.path.expanduser() method
full_path = os.path.expanduser(path)
  
# print the path after
# expanding initial ~ component
# in the given path
print(full_path)
  
  
# While expansion, An initial
# ~user component is looked
# up directly in the password directory.
  
# Path having an initial
# ~user component
path = "~ihritik / file.txt"
  
# Expand the initial ~user
# component in the given path
# using os.path.expanduser() method
full_path = os.path.expanduser(path)
  
# print the path after
# expanding the initial ~user
# component in the given path
print(full_path)

输出：

/home/ihritik/file.txt
/home/GeeksForGeeks/file.txt
/home/ihritik/file.txt

代码 #2：使用 os.path.expanduser() 方法（在 Windows 上）

Python3

# Python program to explain os.path.expandvars() method 
     
# importing os.path module 
import os.path
   
# On Windows % name % expansions
# are supported in addition to
# $name and ${name}
   
# Path 1
path1 = R"% HOMEPATH %\Directory\file.txt"
   
# Path 2
path2 = R"C:\Users\$USERNAME\Directory\file.txt"
   
# Path 3
path3 = R"${TEMP}\file.txt"
   
# Expand the environment variables
# with their corresponding 
# value in the given paths  
exp_var1 = os.path.expandvars(path1)
exp_var2 = os.path.expandvars(path2)
exp_var3 = os.path.expandvars(path3)
   
# Print the given paths with
# environment variables expanded
print(exp_var1)
print(exp_var2)
print(exp_var3)
   
   
# In the above example 
# os.path.expandvars() method
# replaced the environment variables
# 'HOMEPATH', 'USERNAME' and 'TEMP'
# with their corresponding values

输出：

\\Users\\Hritik\\\Directory\\file.txt
C:\\Users\\Hritik\\\Directory\\file.txt
C:\\Users\\Hritik\\AppData\\Local\\Temp\\file.txt

代码#3： 3：如果环境变量不存在

Python3

# Python program to explain os.path.expandvars() method 
     
# importing os.path module 
import os.path
   
# If environment variable 
# is malformed or does not exists
# then the given path will be
# left unchanged
   
# Path
path = R"${MYHOME}/Directory / file.txt"
   
# Expand the environment variables
# with their corresponding 
# value in the given paths  
exp_var = os.path.expandvars(path)
   
# Print the given patha with
# environment variables expanded
print(exp_var)
   
   
# As 'MYHOME' environment variable
# does not exists so
# os.path.expandvars() method
# will return the given path
# unchanged

输出：

${MYHOME}/Directory/file.txt

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