In some cases, the program needs to reverse traversal, this time by the reversed () function, which may receive various sequence (tuple list, interval, etc.) parameters, and then returns a "reverse order" in France on behalf of the device, this function has no effect on the parameter itself.
In an interactive interpreter, the function test process is as follows:
>>> a = range(10) >>> [x for x in reversed(a)] [9, 8, 7, 6, 5, 4, 3, 2, 1, 0]
As seen from the above code, via the reversed () function to get the range (10) of the inverted sequence; if a visit again, and will not see a change:
>>> a range(0, 10)
the reversed () may of course be inverted list, tuples. Test code, for example, as follows:
>>> b = ['a', 'fkit', 20, 3.4, 50] >>> [x for x in reversed(b)] [50, 04/03, 20 'fkit', 'a']
As mentioned earlier, str sequence actually, it can also be achieved by this function without affecting the string itself, the string in reverse order traversal. Test code, for example, as follows:
>>> c = 'Hello,Charlie' >>> [x for x in reversed(c)] ['e', 'i', 'l', 'r', 'a', 'h', 'C', ',', 'o', 'l', 'l', 'e', 'H']