14、 切片 切片(slicing)可将一个可迭代对象中元素的子集,创建为一个新的可迭代对象。切片的语法是[可迭代对象][[起始索引:结束索引]]。起始索引(start index)是开始切片的索引,结束索引(end index)是结束索引的位置。切片时包含起始索引位置的元素,但不包括结束索引位置的元素。果起始索引是0,那么可以将起始索引...
start (optional)- Starting integer where the slicing of the object starts. Default toNoneif not provided. stop- Integer until which the slicing takes place. The slicing stops at indexstop -1 (last element). step (optional)- Integer value which determines the increment between each index for ...
14、 切片 切片(slicing)可将一个可迭代对象中元素的子集,创建为一个新的可迭代对象。切片的语法是[可迭代对象][[起始索引:结束索引]]。起始索引(start index)是开始切片的索引,结束索引(end index)是结束索引的位置。切片时包含起始索引位置的元素,但不包括结束索引位置的元素。果起始索引是0,那么可以将起始索引...
char_at_index_2 = string1[2] # 结果为 'l' (5)切片(Slicing) 使用方括号和切片语法可以获取字符串的子串。 substring = string1[0:5] # 结果为 'Hello' (6)长度(Length) 使用len()函数可以获取字符串的长度。 length_of_string = len(combined_string) # 结果为 13 (7)大小写转换 使用字符串的...
Slicing won’t be useful for this, as strings areimmutabledata types, in terms of Python, which means that they can’t be modified. What we can do is create a new string based on the old one: We’re not changing the underlying string that was assigned to it before. We’re assigning...
index -5 -4 -3 -2 -1# last item print(my_list[-1])#output e# fifth last item print(my_list[-5])#output:p Python中的列表切片 我们可以使用切片运算符 : 访问或切片列表中的一系列项目。 # List slicing in Pythonmy_list = ['p','r','o','g','r','a','m','i','z']# ele...
We're slicing from the second item (index 1) onward and then we're slicing up to, but not including, the second item. This made a new list with the first item (watermelon) moved to the end of the list.Negative indexes work tooNote that negative indexes work the same way with ...
Figure 3-2. String slicing字符串切片: The string Monty Python is shown along with its positive and negative indexes; two substrings are selected using “slice” notation. The slice [m,n] contains the characters from position m through n-1. ...
Negative List Indexing Index -1 corresponds to the last element in the list, while the first element is -len(words), as shown below:Python >>> words[-1] 'corge' >>> words[-2] 'quux' >>> words[-len(words)] 'foo' Slicing also works with lists and tuples. For example, the...
In this video, you’ll practice list indexing and slicing. The elements of a list can be accessed by an index. To do that, you name the list, and then inside of a pair of square brackets you use an index number, like what I’m showing right here. That…