python列表(list)

#str  #类,字符串
#name = "raitorei" #创建一个对象

#list #类,列表
##############list类中提供的方法(灰魔法)##################
# 对象.方法(..) ,li对象调用append方法
# li = [1,2,3,4]
# 1在原来值最后追加
# li.append(5)
# li.append([11,22])
# li.append("raito")
# print(li)

# 2.清空列表
# li.clear()
# print(li)

# 3.拷贝,浅拷贝
# v = li.copy()
# print(v)

# 4.计算元素出现的次数
# v = li.count(2)
# print(v)

# 5.扩展愿列表
# li = [1,2,3,4,5]
# li.append([4645,"fdafafd"])#[1, 2, 3, 4, 5, [4645, 'fdafafd']]
# li.extend([4645,"fdafafd"])#[1, 2, 3, 4, 5, 4645, 'fdafafd']
# li.extend("风动旛动")       #[1, 2, 3, 4, 5, '风', '动', '旛', '动']
# print(li)

# 6.根据值获取改值索引位置,左边有限
# li = [1,2,3,4,5,2]
# v = li.index(2)
# print(v)

# 7.在指定位置插入元素
# li = [1,2,3,4,5]
# li.insert(0,99)
# print(li)

# 8.删除某个值并获取当前的值(默认最后一个,可以指定索引)
# li = [1,2,3,4,5]
# v = li.pop()
# v = li.pop(1)
# print(li)
# print(v)

# 9.删除列表中指定的值，左边优先
# li = [1,2,3,4,5]
# li.remove(2)
# print(li)
# ps: pop,remove,del,li[0],del li[7:9],clear

# 10.讲列表翻转
# li = [1,2,3,4,5]
# li.reverse()
# print(li)

# 11.排序
# li = [1,2,3,4,5]
# # li.sort()
# li.sort(reverse=True)
# print(li)

###############深灰魔法####################
# 1.列表格式：中括号括起来,英文逗号分割每个元素,
#            列表中的元素可以使数字，字符串，列表，布尔值
#            集合内部可以防止任何东西
# li = [1,2,"tsukirei",["轰",["Carole","Tuesday"],"绿谷"],"凌江"]
# 2.索引取值
# print(li[2])
# 3.切片取值,切片结果也是列表
# print(li[2:5])
# 4.for循环取值
# for i in li:
#     print(i)
# li = [1,2,"tsukirei",["轰",["Carole","Tuesday"],"绿谷"],"凌江"]
# 5.索引修改
# li[1] = 120
# print(li)
# li[1] = [1,2,3,4]
# print(li)
# 6.切片修改
# li[0:1] = [10,20]
# print(li)
# 7.删除
# del li[1]
# print(li)
# 8.是否存在某值
# li = [1,2,"tsukirei",["轰",["Carole","Tuesday"],"绿谷"],"凌江"]
# v = 1 in li
# print(v)
# 9.索引嵌套取值
# li = [1,2,9,"tsukirei",["轰",["Carole",[12,13],"Tuesday"],"绿谷"],"凌江"]
# print(li[4][1][1][0])
# 10.转换(字符串可以转列表,数字不能直接转列表)
# s = "qavapkhvakfjdkdf"
# li = list(s)
# print(li)
# s = 123
# li = list(str(s))
# print(li)
# 11.列表转字符串
# li = [1,2,3,"123","raito"]
# r = str(li)
# print(r)    #[1, 2, 3, '123', 'raito']
# 如果有数字和字符串只能自己循环
# s = ""
# for i in li:
#     s += str(i)
# print(s)
# 如果只有字符串,可以用下面的方法
# li = ["123","raito"]
# v = "".join(li)
# print(v)

#补充：字符串创建不可以修改
# li = [1,2,3,4]
# print(li[0])
# li[0] = 546
# print(li)
s = "raitorei"
print(s[0])
s[0] = "e"  #报错
print(s)