cd是用于更改工作目录的shell命令。
如何更改Python中的当前工作目录?
cd是用于更改工作目录的shell命令。
如何更改Python中的当前工作目录?
当前回答
cd()使用生成器和装饰器很容易编写。
from contextlib import contextmanager
import os
@contextmanager
def cd(newdir):
prevdir = os.getcwd()
os.chdir(os.path.expanduser(newdir))
try:
yield
finally:
os.chdir(prevdir)
然后,即使抛出异常,目录也会恢复:
os.chdir('/home')
with cd('/tmp'):
# ...
raise Exception("There's no place like /home.")
# Directory is now back to '/home'.
其他回答
import os
abs_path = 'C://a/b/c'
rel_path = './folder'
os.chdir(abs_path)
os.chdir(rel_path)
您可以将两者与os.chdir(abs_path)或os.chdir(rel_path)一起使用,不需要调用os.getcwd()来使用相对路径。
os.chdir()是cd的Python版本。
下面是一个上下文管理器更改工作目录的示例。它比其他地方提到的ActiveState版本更简单,但这可以完成任务。
上下文管理器:cd
import os
class cd:
"""Context manager for changing the current working directory"""
def __init__(self, newPath):
self.newPath = os.path.expanduser(newPath)
def __enter__(self):
self.savedPath = os.getcwd()
os.chdir(self.newPath)
def __exit__(self, etype, value, traceback):
os.chdir(self.savedPath)
或者使用ContextManager尝试更简洁的等效方法(如下)。
实例
import subprocess # just to call an arbitrary command e.g. 'ls'
# enter the directory like this:
with cd("~/Library"):
# we are in ~/Library
subprocess.call("ls")
# outside the context manager we are back wherever we started.
更改脚本进程的当前目录很简单。我认为问题实际上是如何更改调用python脚本的命令窗口的当前目录,这非常困难。Windows中的Bat脚本或Bash shell中的Bash脚本可以使用普通的cd命令执行此操作,因为shell本身就是解释器。在Windows和Linux中,Python都是一个程序,任何程序都不能直接更改其父环境。然而,将一个简单的shell脚本与一个Python脚本相结合来完成大部分困难的工作,可以获得所需的结果。例如,为了制作一个带有向后/向前/选择重新访问遍历历史的扩展cd命令,我编写了一个由简单的bat脚本调用的相对复杂的Python脚本。遍历列表存储在文件中,目标目录位于第一行。当python脚本返回时,bat脚本读取文件的第一行,并将其作为cd的参数
if _%1 == _. goto cdDone
if _%1 == _? goto help
if /i _%1 NEQ _-H goto doCd
:help
echo d.bat and dSup.py 2016.03.05. Extended chdir.
echo -C = clear traversal list.
echo -B or nothing = backward (to previous dir).
echo -F or - = forward (to next dir).
echo -R = remove current from list and return to previous.
echo -S = select from list.
echo -H, -h, ? = help.
echo . = make window title current directory.
echo Anything else = target directory.
goto done
:doCd
%~dp0dSup.py %1
for /F %%d in ( %~dp0dSupList ) do (
cd %%d
if errorlevel 1 ( %~dp0dSup.py -R )
goto cdDone
)
:cdDone
title %CD%
:done
python脚本dSup.py是:
import sys, os, msvcrt
def indexNoCase ( slist, s ) :
for idx in range( len( slist )) :
if slist[idx].upper() == s.upper() :
return idx
raise ValueError
# .........main process ...................
if len( sys.argv ) < 2 :
cmd = 1 # No argument defaults to -B, the most common operation
elif sys.argv[1][0] == '-':
if len(sys.argv[1]) == 1 :
cmd = 2 # '-' alone defaults to -F, second most common operation.
else :
cmd = 'CBFRS'.find( sys.argv[1][1:2].upper())
else :
cmd = -1
dir = os.path.abspath( sys.argv[1] ) + '\n'
# cmd is -1 = path, 0 = C, 1 = B, 2 = F, 3 = R, 4 = S
fo = open( os.path.dirname( sys.argv[0] ) + '\\dSupList', mode = 'a+t' )
fo.seek( 0 )
dlist = fo.readlines( -1 )
if len( dlist ) == 0 :
dlist.append( os.getcwd() + '\n' ) # Prime new directory list with current.
if cmd == 1 : # B: move backward, i.e. to previous
target = dlist.pop(0)
dlist.append( target )
elif cmd == 2 : # F: move forward, i.e. to next
target = dlist.pop( len( dlist ) - 1 )
dlist.insert( 0, target )
elif cmd == 3 : # R: remove current from list. This forces cd to previous, a
# desireable side-effect
dlist.pop( 0 )
elif cmd == 4 : # S: select from list
# The current directory (dlist[0]) is included essentially as ESC.
for idx in range( len( dlist )) :
print( '(' + str( idx ) + ')', dlist[ idx ][:-1])
while True :
inp = msvcrt.getche()
if inp.isdigit() :
inp = int( inp )
if inp < len( dlist ) :
print( '' ) # Print the newline we didn't get from getche.
break
print( ' is out of range' )
# Select 0 means the current directory and the list is not changed. Otherwise
# the selected directory is moved to the top of the list. This can be done by
# either rotating the whole list until the selection is at the head or pop it
# and insert it to 0. It isn't obvious which would be better for the user but
# since pop-insert is simpler, it is used.
if inp > 0 :
dlist.insert( 0, dlist.pop( inp ))
elif cmd == -1 : # -1: dir is the requested new directory.
# If it is already in the list then remove it before inserting it at the head.
# This takes care of both the common case of it having been recently visited
# and the less common case of user mistakenly requesting current, in which
# case it is already at the head. Deleting and putting it back is a trivial
# inefficiency.
try:
dlist.pop( indexNoCase( dlist, dir ))
except ValueError :
pass
dlist = dlist[:9] # Control list length by removing older dirs (should be
# no more than one).
dlist.insert( 0, dir )
fo.truncate( 0 )
if cmd != 0 : # C: clear the list
fo.writelines( dlist )
fo.close()
exit(0)
如果您使用的是相对较新的Python版本,也可以使用上下文管理器,例如:
from __future__ import with_statement
from grizzled.os import working_directory
with working_directory(path_to_directory):
# code in here occurs within the directory
# code here is in the original directory
更新
如果你喜欢自己动手:
import os
from contextlib import contextmanager
@contextmanager
def working_directory(directory):
owd = os.getcwd()
try:
os.chdir(directory)
yield directory
finally:
os.chdir(owd)