最后,我们用类图来表示负数索引切片的概念及其与列表的关系: usesList+list: List+index: int+slice(from: int, to: int) : ListNegativeIndex+index: int+fromEnd: bool 结尾 通过本篇文章,我们学习了 Python 负数索引切片的基本概念和实现步骤。希望这对你理解序列操作有所帮助!在日常编程中,灵活运用负数索引...
官方文档释义：Called to implement evaluation of self[key]. For sequence types, the accepted keys should be integers and slice objects. Note that the special interpretation of negative indexes (if the class wishes to emulate a sequence type) is up to the __getitem__() method. If key is of...
Python list slice negative step With a negative step, we take every nth element from the end. The start index must be greater than the end index. main.py #!/usr/bin/python vals = [-2, -1, 0, 1, 2, 3, 4, 5, 6] print(vals[5:0:-2]) print(vals[::-2]) print(vals[::...
语法:object.__getitem__(self, key) 官方文档释义:Called to implement evaluation of self[key]. For sequence types, the accepted keys should be integers and slice objects. Note that the special interpretation of negative indexes (if the class wishes to emulate...
官方文档释义:Called to implement evaluation of self[key]. For sequence types, the accepted keys should be integers and slice objects. Note that the special interpretation of negative indexes (if the class wishes to emulate a sequence type) is up to themethod. If key is of an inappropriate ...
return self.data[index] else: msg = "{cls.__name__} indices must be integers" raise TypeError(msg.format(cls=cls)) l = MyList(["My", "name", "is", "Python猫"]) ### 输出结果: key is : 3 Python猫 key is : slice(None, 2, None) ...
官方文档释义:Called to implement evaluation of self[key]. For sequence types, the accepted keys should be integers and slice objects. Note that the special interpretation of negative indexes (if the class wishes to emulate a sequence type) is up to the__getitem__()method. If key is of an...
slice_object = slice(3) print(py_string[slice_object])# Pyt# start = 1, stop = 6, step = 2# contains 1, 3 and 5 indicesslice_object = slice(1,6,2)print(py_string[slice_object])# yhn Run Code Output Pyt yhn Example 3: Get substring using negative index ...
li[::0] # 报错(ValueError: slice step cannot be zero) 上述的某些例子对于初学者(甚至很多老手)来说,可能还不好理解,但是它们都离不开切片的基本语法,所以为方便起见,我将它们也归入基础用法中。 对于这些样例,我个人总结出两条经验: (1)牢牢记住公式[i : i+n : m],当出现缺省值时,通过想象把公式补...
Output:lroWollHere the index values are taken from end to start. The substring is made from indexes 1 to 7 from end to start. s1 = s[8:1:-2] print(s1) Output:lool Python slice works with negative indexes too, in that case, the start_pos is excluded and end_pos is included in ...