python数据类型

　　python中列表是最常用的数据类型之一，由多个元素组成的集合，每个元素都有一个位置或者叫索引，索引的值从0开始，往后顺序递推，最大值为列表长度-1
　　例如aa = [1, 2, 3, 4, 5]  print(aa[0])  # 1 print(aa[1])  # 2 print(aa[2])  # 3常用方法索引、切片# 　索引　切片 l = [＂a＂, ＂b＂, ＂c＂, ＂d＂, ＂e＂, ＂f＂] # 优先掌握部分 print(l[1:5]) print(l[1:5:2]) print(l[2:5]) print(l[-1]) ＂＂＂ [＂b＂, ＂c＂, ＂d＂, ＂e＂] [＂b＂, ＂d＂] [＂c＂, ＂d＂, ＂e＂] f ＂＂＂ # 了解 print(l[-1:-4]) print(l[-4:-1]) print(l[-4:]) l = [＂a＂, ＂b＂, ＂c＂, ＂d＂, ＂e＂, ＂f＂] print(l[-2:]) ＂＂＂ [] [＂c＂, ＂d＂, ＂e＂] [＂c＂, ＂d＂, ＂e＂, ＂f＂] [＂e＂, ＂f＂] ＂＂＂追加元素append()hobbies = [＂play＂, ＂eat＂, ＂sleep＂, ＂study＂] hobbies.append(＂girls＂) print(hobbies) # [＂play＂, ＂eat＂, ＂sleep＂, ＂study＂, ＂girls＂]删除元素pop()
　　如果pop()里面没加参数 则默认删除最后一个元素hobbies = [＂play＂, ＂eat＂, ＂sleep＂, ＂study＂, ＂run＂, ＂girl＂] x = hobbies.pop(1)  # 不是单纯的删除，是删除并且把删除的元素返回，我们可以用一个变量名去接收该返回值 print(x) print(hobbies)  x = hobbies.pop(0) print(x)  x = hobbies.pop(0) print(x)  x = hobbies.pop() print(x) ＂＂＂ eat [＂play＂, ＂sleep＂, ＂study＂, ＂run＂, ＂girl＂] play sleep girl ＂＂＂del
　　del和pop() 不一样， 他没有返回值，只是单纯的将参数里面索引对应的元素从列表里面删除
　　这种删除方式不光在列表中有用，在后面的元组和字典里也是有用的hobbies = [＂play＂, ＂eat＂, ＂sleep＂, ＂study＂] del hobbies[1]  # 单纯的删除 print(hobbies)  # [＂play＂, ＂sleep＂, ＂study＂]remove()
　　remove()参数是具体的元素值,不是索引，也没有返回值hobbies = [＂play＂, ＂eat＂, ＂sleep＂, ＂study＂] hobbies.remove(＂eat＂)  # 单纯的删除，并且是指定元素去删除 print(hobbies)  # [＂play＂, ＂sleep＂, ＂study＂]用append()和pop()队列和堆栈
　　队列：是一种数据结构，其特点是先进先出，就和排队一样，排在最前面的人优先买到东西
　　堆栈: 是一种数据结构，其特点是后进先出，就和往桶里面放东西一样，最后放进去的,往往是最先拿出来# 队列：先进先出 queue_l = [] # 入队 queue_l.append(＂first＂) queue_l.append(＂second＂) queue_l.append(＂third＂) print(queue_l)  # [＂first＂, ＂second＂, ＂third＂] # 出队 print(queue_l.pop(0))  # first print(queue_l.pop(0))  # second print(queue_l.pop(0))  # third # 堆栈:先进后出，后进先出 l = [] # #入栈 l.append(＂first＂) l.append(＂second＂) l.append(＂third＂) # #出栈 print(l)  # [＂first＂, ＂second＂, ＂third＂] print(l.pop())  # third print(l.pop())  # second print(l.pop())  # first计算列表的长度hobbies=[＂play＂,＂eat＂,＂sleep＂,＂study＂] print(len(hobbies))  # 4列表是否包含某个元素
　　对于字符串来说也是可以的# 　　　　包含in hobbies = [＂play＂, ＂eat＂, ＂sleep＂, ＂study＂] print(＂sleep＂ in hobbies)  # True  msg = ＂hello world sz＂ print(＂sz＂ in msg)  # True插入元素insert()hobbies = [＂play＂, ＂eat＂, ＂sleep＂, ＂study＂, ＂eat＂, ＂eat＂] hobbies.insert(1, ＂walk＂) print(hobbies) hobbies.insert(1, [＂walk1＂, ＂walk2＂, ＂walk3＂]) print(hobbies) ＂＂＂ [＂play＂, ＂walk＂, ＂eat＂, ＂sleep＂, ＂study＂, ＂eat＂, ＂eat＂] [＂play＂, [＂walk1＂, ＂walk2＂, ＂walk3＂], ＂walk＂, ＂eat＂, ＂sleep＂, ＂study＂, ＂eat＂, ＂eat＂] ＂＂＂统计个数count()hobbies = [＂play＂, ＂eat＂, ＂sleep＂, ＂study＂, ＂eat＂, ＂eat＂] print(hobbies.count(＂eat＂))  # 3列表合并extend()
　　list1.extend(list2) 将list2中的元素从list1的末尾添加上list1中hobbies = [＂play＂, ＂eat＂, ＂sleep＂, ＂study＂, ＂eat＂, ＂eat＂] hobbies.extend([＂walk1＂, ＂walk2＂, ＂walk3＂]) print(hobbies)   # [＂play＂, ＂eat＂, ＂sleep＂, ＂study＂, ＂eat＂, ＂eat＂, ＂walk1＂, ＂walk2＂, ＂walk3＂]获取某个元素的索引index()如果列表中有当前元素,则返回当前元素第一次出现的索引 如果列表中没有当前元素，没有就报错hobbies = [＂play＂, ＂eat＂, ＂sleep＂, ＂study＂, ＂eat＂, ＂eat＂] print(hobbies.index(＂eat＂))  # 1 print(hobbies.index(＂girl＂))  # 报错清空元素clear()hobbies = [＂play＂, ＂eat＂, ＂sleep＂, ＂study＂, ＂eat＂, ＂eat＂] hobbies.clear() print(hobbies)  # []列表拷贝copy()
　　列表拷贝属于浅拷贝, 修改列表里面的元素会相互影响，切记，这里不展开说，后面会详细说hobbies = [＂play＂, ＂eat＂, ＂sleep＂, ＂study＂, ＂eat＂, ＂eat＂] l = hobbies.copy()  # [＂play＂, ＂eat＂, ＂sleep＂, ＂study＂, ＂eat＂, ＂eat＂] print(l)
　　列表反转reverse()l = [1, 2, 3, 4, 5] l.reverse() print(l)  # [5, 4, 3, 2, 1]列表排序sort()l = [100, 9, -2, 11, 32] l.sort() print(l)  # [-2, 9, 11, 32, 100]  l = [1, 4, 5, 2, 6] l.sort(reverse=True) print(l)  # [6, 5, 4, 2, 1]