(2)创建一个列表,一般创建列表时,变量的名字会使用复数 (3)列表的索引可以是负数 (4)如果索引是负数,则从后向前获取元素,-1表示倒数第一个,-2表示倒数第二个,以此类推 (5)通过切片来获取指定的元素 - 语法:列表[起始:结束] my_lists = [10,'hello',None,40,50] print(my_lists[0:2]) #只打印10...
The extend() method does not have to append lists, you can add any iterable object (tuples, sets, dictionaries etc.).Example Add elements of a tuple to a list: thislist = ["apple", "banana", "cherry"] thistuple = ("kiwi", "orange") thislist.extend(thistuple) print(thislist) ...
When we say that lists are ordered, it means that the items have a defined order, and that order will not change. If you add new items to a list, the new items will be placed at the end of the list. Note:There are somelist methodsthat will change the order, but in general: the...
You are given two linked lists representing two non-negative numbers. The digits are stored in reverse order and each of their nodes contain a single digit. Add the two numbers and return it as a linked list. Input:(2 -> 4 -> 3) + (5 -> 6 -> 4) Output:7 -> 0 -> 8 代码:...
You are given two linked lists representing two non-negative numbers. The digits are stored in reverse order and each of their nodes contain a single digit. Add the two numbers and return it as a linked list. Input:(2 -> 4 -> 3) + (5 -> 6 -> 4) ...
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for i in [0, 1, 2, 3]: print(i) 前面的for循环实际上遍历了它的子句,变量i在每次迭代中被设置为[0, 1, 2, 3]列表中的一个连续值。 一种常见的 Python 技术是使用range(len(someList))和for循环来迭代列表的索引。例如,在交互式 Shell 中输入以下内容: >>> supplies = ['pens', 'staplers'...
job_lists=[]forjobinjob_list:#创建一个Item对象,用于存放匹配的目标数据 item=FirproItem()#想要显示全,就需要extract()方法,转换成字符串输出 item["name"]=job.xpath(".//td[1]//a/text()[1]").extract()item["percent"]=job.xpath(".//td[2]//span")item["company"]=job.xpath(".//td...
# testcase.addTests(test_case)#print(testcase)testcase.addTests(discover)# 直接加载 discover 可以兼容python2和3print(testcase)returntestcase #===定义发送邮件===defsend_mail(file_new):#---1.跟发件相关的参数---smtpserver='smtp.mxhichina.com'#发件服务器 port=0#端口 username='nXXX@ceXx...
a = a + bprint( a)# [1, 2, 3, 4] Run Code Python extend() Vs append() If you need to add the item itself (rather than its elements), use theappend()method. a1 = [1,2] a2 = [1,2] b = (3,4)# add items of b to the a1 lista1.extend(b)# [1, 2, 3, 4]prin...