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import os

def symbolic_notation(mode):
    notation = list(reversed('rwxrwxrwx'))
    return ''.join(mode & 2**i and notation[i] or '-' for i in range(8, -1, -1))
    
print symbolic_notation(os.stat('blub').st_mode)

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import os

CHMOD_TRANS_DATA = ("x","w","r")*3

def symbolic_notation(mode):
    result = []
    for i in xrange(8, -1, -1):
        # Wie kann man "m" besser benennen???
        m = mode & 2**i 

        # Was passiert hier genau?
        symbols = m and CHMOD_TRANS_DATA[i] or '-'

        result.append(symbols)

    return ''.join(result)

test_data = (0100000, 0100123, 0100456, 0100765)
for mode in test_data:

    print "%o -> %s" % (mode, symbolic_notation(mode))
    print "="*80

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>>> ''.join(0755 & 0400 >> i and x or '-' for i, x in enumerate('rwxrwxrwx'))
'rwxr-xr-x'

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def symbolic_notation1(mode):
    """
    >>> symbolic_notation1(644)
    u'rw-r--r--'
    >>> symbolic_notation1(40755)
    u'rwxr-xr-x'
    >>> symbolic_notation1("777")
    u'rwxrwxrwx'
    """
    return ''.join(
        mode & 0400 >> i and x or '-' for i, x in enumerate('rwxrwxrwx')
    )

def symbolic_notation2(mode):
    """
    >>> symbolic_notation2(644)
    u'rw-r--r--'
    >>> symbolic_notation2(40755)
    u'rwxr-xr-x'
    >>> symbolic_notation2("777")
    u'rwxrwxrwx'
    """
    result = []
    for i, x in enumerate('rwxrwxrwx'):
        m = mode & 0400 >> i
        symbol = m and x or '-'
        result.append(symbol)

    return ''.join(result)


CHMOD_TRANS_DATA = (
    u"---", u"--x", u"-w-", u"-wx", u"r--", u"r-x", u"rw-", u"rwx",
)
def symbolic_notation3(mode):
    """
    >>> symbolic_notation3(644)
    u'rw-r--r--'
    >>> symbolic_notation3(40755)
    u'rwxr-xr-x'
    >>> symbolic_notation3("777")
    u'rwxrwxrwx'
    """
    mode = mode & 0777 # strip "meta info"
    mode_string = u"%o" % mode

    return u''.join(CHMOD_TRANS_DATA[int(num)] for num in mode_string)

if __name__ == "__main__":
    import doctest
    print doctest.testmod(verbose=False)

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...
3 items had failures:
   3 of   3 in __main__.symbolic_notation1
   3 of   3 in __main__.symbolic_notation2
   3 of   3 in __main__.symbolic_notation3
***Test Failed*** 9 failures.
TestResults(failed=9, attempted=9)

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CHMOD_TRANS_DATA = (
    u"---", u"--x", u"-w-", u"-wx", u"r--", u"r-x", u"rw-", u"rwx"
)
def chmod_symbol(octal_value):
    """
    Transform a os.stat().st_octal_value octal value to a symbolic string.
    ignores meta infromation like SUID, SGID or the Sticky-Bit.
    e.g. 40755 -> rwxr-xr-x
    >>> chmod_symbol(644)
    u'rw-r--r--'
    >>> chmod_symbol(40755)
    u'rwxr-xr-x'
    >>> chmod_symbol("777")
    u'rwxrwxrwx'
    """
    octal_value_string = str(octal_value)[-3:] # strip "meta info"
    return u''.join(CHMOD_TRANS_DATA[int(num)] for num in octal_value_string)

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def chmod_sym(val):
    def tripple(v):
        return "-r"[bool(v & 4)] + "-w"[bool(v & 2)] + "-x"[bool(v & 1)]
    return tripple(val / 64) + tripple(val / 8) + tripple(val)

Code: Alles auswählen

def chmod_sym(val):
    """
    >>> chmod_sym(644)
    u'rw-r--r--'
    >>> chmod_sym(40755)
    u'rwxr-xr-x'
    >>> chmod_sym("777")
    u'rwxrwxrwx'
    """
    val = int(val)
    def tripple(v):
        return "-r"[bool(v & 4)] + "-w"[bool(v & 2)] + "-x"[bool(v & 1)]
    return tripple(val / 64) + tripple(val / 8) + tripple(val)

if __name__ == "__main__":
    import doctest
    print doctest.testmod(verbose=False)

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**********************************************************************
File "test.py", line 4, in __main__.chmod_sym
Failed example:
    chmod_sym(644)
Expected:
    u'rw-r--r--'
Got:
    '-w----r--'
**********************************************************************
File "test.py", line 6, in __main__.chmod_sym
Failed example:
    chmod_sym(40755)
Expected:
    u'rwxr-xr-x'
Got:
    'r--rw--wx'
**********************************************************************
File "test.py", line 8, in __main__.chmod_sym
Failed example:
    chmod_sym("777")
Expected:
    u'rwxrwxrwx'
Got:
    'r----x--x'
**********************************************************************
1 items had failures:
   3 of   3 in __main__.chmod_sym
***Test Failed*** 3 failures.
TestResults(failed=3, attempted=3)