Remove the item at the given position in the list, and return it. If no index is specified, a.pop() removes and returns the last item in the list. (The square brackets around the i in the method signature denote
return a_list[-1] def first(a_list): return a_list[0] 1. 2. 3. 4. 5. 或使用operator.itemgetter: >>> import operator >>> last = operator.itemgetter(-1) >>> first = operator.itemgetter(0) 1. 2. 3. 在任一情况下: >>> last(a_list) 'three' >>> first(a_list) 'zero' ...
1. for i in [1,2,3] 2. print i 1. 2. 上面代码中in关键字后面的对象[1,2,3]是一个list,也是一个集合。 但in关键字后面的对象其实不必是一个集合。后面接一个序列对象也是合法的。 例如 1. myrange = MyRange(0, 10) 2. for i in myrange: 3. print i 1. 2. 3. 上面代码中的myra...
6、L.pop([index]) -> item -- remove and return item at index (default last) 移除列表中的一个元素(默认最后一个元素),并且返回该元素的值 >>> list3 ['', 'zhangsan', 'mayun', 'lishi', 'laowang', 'liuqiangdong'] >>> list3 ['', 'zhangsan', 'mayun', 'lishi', 'laowang', '...
Python提供了5中内置的序列类型:bytearray、bytes、list、str与tuple,序列类型支持成员关系操作符(in)、大小计算函数(len())、分片([]),并且是可可迭代的。 1.1 元组 元组是个有序序列,包含0个或多个对象引用,使用小括号包裹。元组是固定的,不能替换或删除其中包含的任意数据项。
Remove and return item at index (default last). Raises IndexError if list is empty or index is out of range. """ pass 翻译:默认移除对象的最后一个值 如果列表为空或者索引超出范围,则抛出IndexError View Code 9.remove def remove(self, *args, **kwargs): # real signature unknown ...
Return sends a specified value back to its caller whereas Yield can produce a sequence of values. We should use yield when we want to iterate over a sequence, but don't want to store the entire sequence in memory. import sys # for example when reading a large file, we only care about...
last_student = students[-1] # "Charlie"2.1.1.2 列表的增删改操作 列表提供了丰富的内置方法来改变其内容: •增:append()、extend()、insert() •删:remove()、pop()、del关键字、clear() •改:直接赋值或使用list[index] = new_value
print("这是__new__方法")instance=super().__new__(cls)# 可以在这里自定义对象的创建过程return...
Print the second item of the list: thislist = ["apple", "banana", "cherry"] print(thislist[1]) Try it Yourself » Negative IndexingNegative indexing means beginning from the end, -1 refers to the last item, -2 refers to the second last item etc.Example...