如何在Python中更改目录(cd)?

时间:2009-01-10 20:28:17

标签: python

cd和shell命令一样,用于更改工作目录。

如何在Python中更改当前的工作目录?

15 个答案:

答案 0 :(得分:652)

您可以使用以下命令更改工作目录:

import os

os.chdir(path)

使用此方法时,有两个最佳做法:

  1. 在无效路径上捕获异常(WindowsError,OSError)。如果抛出异常,请不要执行任何递归操作,尤其是破坏性操作。他们将在旧的道路上运作而不是新道路。
  2. 完成后返回旧目录。这可以通过将chdir调用包装在上下文管理器中以异常安全的方式完成,就像Brian M. Hunt在his answer中所做的那样。
  3. 更改子进程中的当前工作目录不会更改父进程中的当前工作目录。对于Python解释器也是如此。您无法使用os.chdir()更改调用进程的CWD。

答案 1 :(得分:281)

以下是更改工作目录的上下文管理器示例。它比其他地方提到的ActiveState version更简单,但这可以完成工作。

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more concise equivalent(below)尝试ContextManager

实施例

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.

答案 2 :(得分:132)

我会像这样使用os.chdir

os.chdir("/path/to/change/to")

顺便说一句,如果您需要确定当前路径,请使用os.getcwd()

更多here

答案 3 :(得分:100)

使用生成器和装饰器很容易编写

cd()

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,目录也会被恢复:

os.chdir('/home')

with cd('/tmp'):
    # ...
    raise Exception("There's no place like home.")
# Directory is now back to '/home'.

答案 4 :(得分:23)

如果您使用的是相对较新版本的Python,您还可以使用上下文管理器,例如this one

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

如果您愿意自己动手​​:

import os
from contextlib import contextmanager

@contextmanager
def working_directory(directory):
    owd = os.getcwd()
    try:
        os.chdir(directory)
        yield directory
    finally:
        os.chdir(owd)

答案 5 :(得分:13)

正如其他人已经指出的那样,上面的所有解决方案只会改变当前进程的工作目录。当您退回到Unix shell时,这会丢失。如果绝望,你可以用这个可怕的黑客来改变Unix上的父shell目录:

def quote_against_shell_expansion(s):
    import pipes
    return pipes.quote(s)

def put_text_back_into_terminal_input_buffer(text):
    # use of this means that it only works in an interactive session
    # (and if the user types while it runs they could insert characters between the characters in 'text'!)
    import fcntl, termios
    for c in text:
        fcntl.ioctl(1, termios.TIOCSTI, c)

def change_parent_process_directory(dest):
    # the horror
    put_text_back_into_terminal_input_buffer("cd "+quote_against_shell_expansion(dest)+"\n")

答案 6 :(得分:12)

os.chdir()cd的Pythonic版本。

答案 7 :(得分:12)

os.chdir()是正确的方式。

答案 8 :(得分:6)

进一步指导Brian指出的方向并基于sh(1.0.8 +)

from sh import cd, ls

cd('/tmp')
print ls()

答案 9 :(得分:4)

如果您想执行类似“cd ..”选项的操作,只需输入:

即可

os.chdir(“..”)

它与Windows cmd中的相同:cd .. 当然 import os 是必要的(例如将其键入代码的第一行)

答案 10 :(得分:2)

import os

abs_path = 'C://a/b/c'
rel_path = './folder'

os.chdir(abs_path)
os.chdir(rel_path)

您可以同时使用os.chdir(abs_path)或os.chdir(rel_path),无需调用os.getcwd()即可使用相对路径。

答案 11 :(得分:0)

更改脚本进程的当前目录非常简单。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,这是非常困难的。 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是一个程序,没有程序可以直接改变其父级环境。但是,简单的shell脚本与执行大多数硬件的Python脚本的组合可以实现所需的结果。例如,为了生成带有遍历/转发/选择重访的遍历历史的扩展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使其成为cd的参数。完整的bat脚本(减去评论简洁)是:

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)

答案 12 :(得分:0)

如果使用spyder and love GUI,则只需单击屏幕右上角的文件夹按钮,然后浏览要用作当前目录的文件夹/目录。 完成此操作后,您可以转到spyder IDE中窗口的文件资源管理器选项卡,您可以在那里看到所有文件/文件夹。 检查您当前的工作目录 转到spyder IDE的控制台,只需键入

pwd

它将打印与之前选择的路径相同的路径。

答案 13 :(得分:0)

path库中的Path对象为此提供了上下文管理器和chdir方法:

from path import Path

with Path("somewhere"):
    ...

Path("somewhere").chdir()

答案 14 :(得分:-5)

为了便于交互使用,ipython内置了所有常见的shell命令。