Python实现list反转实例汇总(3)

    >>> li = [1, 9, 8, 4]
    >>> [elem*2 for elem in li]    
    [2, 18, 16, 8]
    >>> li                         
    [1, 9, 8, 4]
    >>> li = [elem*2 for elem in li]
    >>> li
    [2, 18, 16, 8]

    >>> params = {"server":"mpilgrim", "database":"master", "uid":"sa", "pwd":"secret"}
    >>> params.keys() 
    ['server', 'uid', 'database', 'pwd']
    >>> params.values()
    ['mpilgrim', 'sa', 'master', 'secret']
    >>> params.items()
    [('server', 'mpilgrim'), ('uid', 'sa'), ('database', 'master'), ('pwd', 'secret')]
    >>> [k for k, v in params.items()]              
    ['server', 'uid', 'database', 'pwd']
    >>> [v for k, v in params.items()]              
    ['mpilgrim', 'sa', 'master', 'secret']
    >>> ["%s=%s" % (k, v) for k, v in params.items()]
    ['server=mpilgrim', 'uid=sa', 'database=master', 'pwd=secret']

    >>> li = ["a", "mpilgrim", "foo", "b", "c", "b", "d", "d"]
    >>> [elem for elem in li if len(elem) > 1]     
    ['mpilgrim', 'foo']
    >>> [elem for elem in li if elem != "b"]       
    ['a', 'mpilgrim', 'foo', 'c', 'd', 'd']
    >>> [elem for elem in li if li.count(elem) == 1]
    ['a', 'mpilgrim', 'foo', 'c']