How do I change directory (cd) in Python?
与shell命令中更改工作目录相同。
如何在python中更改当前工作目录?
您可以使用以下方式更改工作目录:
1 2 3 | import os os.chdir(path) |
使用此方法时,需要遵循两个最佳实践:
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。这同样适用于Python解释器。您不能使用
下面是一个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版本简单,但这可以完成任务。
上下文管理器:1 2 3 4 5 6 7 8 9 10 11 12 13 | 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尝试更简洁的等价物(如下)。
例子1 2 3 4 5 6 7 8 | 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. |
我会这样使用
1 | os.chdir("/path/to/change/to") |
顺便说一下,如果您需要确定当前的路径,请使用
这里更多
1 2 3 4 5 6 7 8 9 10 11 | 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,即使在引发异常之后,也会还原目录:
1 2 3 4 5 6 | os.chdir('/home') with cd('/tmp'): # ... raise Exception("There's no place like home.") # Directory is now back to '/home'. |
如果您使用的是相对较新版本的python,那么也可以使用上下文管理器,例如:
1 2 3 4 5 6 7 | 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
如果你喜欢自己滚:
1 2 3 4 5 6 7 8 9 10 11 | import os from contextlib import contextmanager @contextmanager def working_directory(directory): owd = os.getcwd() try: os.chdir(directory) yield directory finally: os.chdir(owd) |
正如其他人已经指出的,上面的所有解决方案都只更改当前流程的工作目录。当您退出到unix shell时,这将丢失。如果你不顾一切的话,你可以用这个可怕的黑客程序更改unix上的父shell目录:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 | 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)+" ") |
进一步深入到布莱恩指出的方向,基于sh(1.0.8+)
1 2 3 4 | from sh import cd, ls cd('/tmp') print ls() |
如果要执行"cd…"选项,只需键入:
O.CHDIR("…")
它与Windows命令:cd中的相同。当然,导入操作系统是必需的(例如,将其键入代码的第一行)
1 2 3 4 5 6 7 | 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),不需要调用os.getcwd()来使用相对路径。
1 2 3 4 5 6 7 8 | #import package import os #change directory os.chdir('my_path') #get location os.getcwd() |
另外,最好在这里检查OS包中所有其他有用的命令:https://docs.python.org/3/library/os.html
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命令窗口中调用Python脚本的当前目录,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命令来执行此操作,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,将简单的shell脚本与执行大多数硬操作的python脚本结合在一起可以获得所需的结果。例如,为了使扩展CD命令具有向后/向前/选择重访的遍历历史,我编写了一个简单的BAT脚本调用的相对复杂的python脚本。遍历列表存储在一个文件中,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。完整的BAT脚本(为了简洁起见减去注释)是:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 | 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:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 | 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] ) + ' ' # 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() + ' ' ) # 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) |
为了便于交互使用,IPython内置了所有常见的shell命令。