字符串是python当中最常用的数据类型,我们用它来处理文本内容,字符串是字符的有序集合,可以使用一对单引号或一对双引号,或者3对双引号来创建。Python 字符串负索引(Negative Indexing)。 原文地址:Python 字符串负索引(Negative Indexing) 编辑于 2021-07-11 20:46 Python Python
#output 5 (as we have list at index 1 and in that list also have index 3)# Error! Only integer can be used for indexing print(my_list[4.0]) 负索引 Python 允许对其序列进行负索引。 -1 的索引是指最后一项,-2 是指倒数第二项,如 - [-4, -3, -2, -1] 。 # Negative indexing in ...
通过切片操作,我们成功获取了列表my_list的前10个元素。 负索引(Negative Indexing) 除了使用正整数索引来获取列表的元素,Python还支持使用负整数索引。负索引表示从列表末尾开始计数,例如,索引-1表示最后一个元素,索引-2表示倒数第二个元素,以此类推。 要获取列表的最后10个元素,我们可以使用负索引来指定切片操作的s...
You can do that usingnegative indexes. In the example above, we don’t know the length of the string, but we know that the word ‘text’ plus the exclamation sign take five indices, so we call negative five to access them. “Remember that Python starts counting indexes from 0 not 1. ...
>>> # Negative Indexing... data_shape = (100, 50, 4)... names = ["John", "Aaron", "Mike", "Danny"]... hello = "Hello World!"... print(data_shape[-1])... print(names[-3:-1])... print(hello[1:-1:2])...4['Aaron', 'Mike']el ol 1. ...
Virtually everything about indexing works the same for tuples.You can also use a negative index, in which case the count starts from the end of the list:Negative List Indexing Index -1 corresponds to the last element in the list, while the first element is -len(words), as shown below...
Negative indexing means start from the end.-1 refers to the last item, -2 refers to the second last item etc.Example Print the last item of the tuple: thistuple = ("apple", "banana", "cherry") print(thistuple[-1]) Try it Yourself » ...
Note that since -0 is the same as 0, negative indices start from -1.需要注意的是索引-0与0同，负数在-1开始。In addition to indexing, slicing is also supported. While indexing is used to obtain individual characters, slicing allows you to obtain substring:除了索引之外，还支持分段索引。当索引...
Sequences also usually support negative indexing, meaning-1is the last item in a sequence,-2is the second-to-last, and so on. SeeWhat are lists in Python?. Sequence (a.k.a. "list-like object") An ordered collection of objects. Sequences have a length (viathe built-inlenfunction),...
Array indexing Numpy offers several ways to index into arrays. slicing importnumpyasnp# Create the following rank 2 array with shape (3, 4)# [[ 1 2 3 4]# [ 5 6 7 8]# [ 9 10 11 12]]a = np.array([[1,2,3,4], [5,6,7,8], [9,10,11,12]])# 利用切片取出下面模型的数...