python学习（索引）
Posted mr-zy
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一.索引
1.索引值从左到右-->从0开始，索引值从右到左-->从-1开始
- 取值格式var[index]
>>> name = "xinfangshuo" >>> >>> name[0] ‘x‘ >>> name[5] ‘n‘ >>> name[-1] ‘o‘ >>> name[-2] ‘u‘
2.注意：整型int和字典dict和集合set不支持索引取值
>>> age = 123 >>> >>> age[1] Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: ‘int‘ object has no attribute ‘__getitem__‘ >>> age = "123" >>> age[1] ‘2‘ >>> name = {"name1":"zhangsan","name2":"lisi","name3":"wangwu"} >>> >>> name[1] Traceback (most recent call last): File "<stdin>", line 1, in <module> KeyError: 1 >>> >>> set = {"zhangsan","lisi","wangwu"} >>> >>> set[1] Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: ‘set‘ object does not support indexing
3.多维数组/列表，索引取值
"""多维数组，索引取值""" >>> name = ("zhangsan","lisi","wangwu","zhaoliu","wangba",("zhengying","lizhipeng","lvlinlin")) >>> >>> name[5][1] ‘lizhipeng‘ >>> >>> list = [1,2,3,4,[5,6,7,[8,9,0]]] >>> >>> list[4][3][1] 9 >>> list[-1][-1][-2] 9
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