列表（list）

1.列表（list）

列表（list），是一个有序且可变的容器，在里面可以存放多个不同类型的元素。

1.1 定义

user_list =  ["苍老师","有坂深雪","大桥未久"]
number_list = [98,88,666,12,-1]
data_list = [1,True,"Alex","宝强","贾乃亮"]

user_list = []
user_list.append("铁锤")  #追加放入use_list中最后，append是经常要用的
user_list.append(123)
user_list.append(True)
print(user_list) # ["铁锤",123,True]

不可变类型：字符串、布尔、整型（已最小，内部数据无法进行修改）

可变类型：列表（内部数据元素可以修改）

1.2 独有功能

Python中为所有的列表类型的数据提供了一批独有的功能。

在开始学习列表的独有功能之前，先来做一个字符串和列表的对比：

• 字符串，不可变，即：创建好之后内部就无法修改。【独有功能都是新创建一份数据】

  name = "alex"
  data = name.upper()
  print(name)
  print(data)
  

• 列表，可变，即：创建好之后内部元素可以修改。【独有功能基本上都是直接操作列表内部，不会创建新的一份数据】

  user_list = ["车子","妹子"]
  user_list.append("嫂子")
  
  print(user_list) # ["车子","妹子","嫂子"]
  

列表中的常见独有功能如下：

1. 追加，在原列表中尾部追加值。

   data_list = []
   
   v1 = input("请输入姓名")
   data_list.append(v1)
   
   v2 = input("请输入姓名")
   data_list.append(v2)
   
   print(data_list) # ["alex","eric"]
   

   # 案例1
   user_list = []
   
   while True:
       user = input("请输入用户名(Q退出)：")
       if user == "Q":
           break
       user_list.append(user)
       
   print(user_list) 
   

   # 案例2
   welcome = "欢迎使用NB游戏".center(30, '*')
   print(welcome)
   
   user_count = 0
   while True:
       count = input("请输入游戏人数：")
       if count.isdecimal():
           user_count = int(count)
           break
       else:
           print("输入格式错误，人数必须是数字。")
   
   
   message = "{}人参加游戏NB游戏。".format(user_count)
   print(message)
   
   
   user_name_list = []
   
   for i in range(1, user_count + 1):
       tips = "请输入玩家姓名（{}/{}）：".format(i, user_count)
       name = input(tips)
       user_name_list.append(name)
   
   print(user_name_list)
   

2. 批量追加，将一个列表中的元素逐一添加另外一个列表。

   tools = ["搬砖","菜刀","榔头"]
   tools.extend( [11,22,33] ) # weapon中的值逐一追加到tools中
   print(tools) # ["搬砖","菜刀","榔头",11,22,33]
   

   tools = ["搬砖","菜刀","榔头"]
   weapon = ["AK47","M6"]
   #tools.extend(weapon) # weapon中的值逐一追加到tools中
   #print(tools) # ["搬砖","菜刀","榔头","AK47","M6"]
   
   weapon.extend(tools)
   print(tools) # ["搬砖","菜刀","榔头"]
   print(weapon) # ["AK47","M6","搬砖","菜刀","榔头"]
   

   # 等价于(扩展)
   weapon = ["AK47","M6"]
   for item in weapon:
       print(item)
   
   # 输出：
   #  AK47
   #  M6
   tools = ["搬砖","菜刀","榔头"]
   weapon = ["AK47","M6"]
   for item in weapon:
       tools.append(item)  
   print(tools) # ["搬砖","菜刀","榔头","AK47","M6"]
   

3. 插入，在原列表的指定索引位置插入值

   user_list = ["苍老师","有坂深雪","大桥未久"]
   user_list.insert(0,"马蓉")
   user_list.insert(2,"李小璐")
   print(user_list)
   #插入不存在的索引会放入不会把报错
   

   # 案例
   name_list = []
   while True:
       name = input("请输入购买火车票用户姓名（Q/q退出）：")
       if name.upper() == "Q":
           break
       if name.startswith("刁"):
           name_list.insert(0, name)
       else:
           name_list.append(name)
   print(name_list)
   

4. 在原列表中根据值删除（从左到右找到第一个删除）【慎用，里面没有会报错】

   user_list = ["王宝强","陈羽凡","Alex","贾乃亮","Alex"]
   user_list.remove("Alex")
   print(user_list)
   
   
   user_list = ["王宝强","陈羽凡","Alex","贾乃亮","Alex"]
   if "Alex" in user_list:
   	user_list.remove("Alex")
   print(user_list)
   
   
   user_list = ["王宝强","陈羽凡","Alex","贾乃亮","Alex"]
   while True:
       if "Alex" in user_list:
           user_list.remove("Alex")
   	else:
           break
   print(user_list)
   

   # 案例：自动抽奖程序
   import random
   
   data_list = ["iphone12", "二手充气女友", "大保健一次", "泰国5日游", "避孕套"]
   
   while data_list:
       name = input("自动抽奖程序，请输入自己的姓名：")
   
       # 随机从data_list抽取一个值出来
       value = random.choice(data_list) # "二手充气女友"
       print( "恭喜{}，抽中{}.".format(name, value) )
       
       data_list.remove(value) # 删除"二手充气女友"
   

5. 在原列表中根据索引踢出某个元素（根据索引位置删除）

   user_list = ["王宝强","陈羽凡","Alex","贾乃亮","Alex"]
   #               0       1      2      3       4
   user_list.pop(1)
   print(user_list) #  ["王宝强","Alex","贾乃亮","Alex"]
   
   user_list.pop() #默认将列表的最后一个值删除
   print(user_list) # ["王宝强","Alex","贾乃亮"]
   
   item = user_list.pop(1)
   print(item) # "Alex"
   print(user_list) # ["王宝强","贾乃亮"]
   

   # 案例：排队买火车票
   
   # ["alex","李杰","eric","武沛齐","老妖","肝胆"]
   user_queue = []
   
   while True:
       name = input("北京~上海火车票，购买请输入姓名排队(Q退出)：")
       if name == "Q":
           break
       user_queue.append(name)
   
   ticket_count = 3
   for i in range(ticket_count):
       username = user_queue.pop(0)
       message = "恭喜{},购买火车票成功。".format(username)
       print(message)
   
   # user_queue = ["武沛齐","老妖","肝胆"]
   faild_user = "、".join(user_queue) # "武沛齐、老妖、肝胆"
   faild_message = "非常抱歉，票已售完，以下几位用户请选择其他出行方式，名单：{}。".format(faild_user)
   print(faild_message)
   

6. 清空原列表

   user_list = ["王宝强","陈羽凡","Alex","贾乃亮","Alex"]
   user_list.clear()
   print(user_list) # []
   

7. 根据值获取索引（从左到右找到第一个删除）【慎用，找不到报错】

   user_list = ["王宝强","陈羽凡","Alex","贾乃亮","Alex"]
   #               0       1      2       3      4
   if "Alex" in user_list:
   	index = user_list.index("Alex")
   	print(index) # 2
   else:
       print("不存在")
   

8. 列表元素排序

   # 数字排序
   num_list = [11, 22, 4, 5, 11, 99, 88]
   print(num_list)
   num_list.sort()  # 让num_list从小到大排序
   num_list.sort(reverse=True)  # # 让num_list从大到小排序
   print(num_list)
   
   
   # 字符串排序
   user_list = ["王宝强", "Ab陈羽凡", "Alex", "贾乃亮", "贾乃", "1"]
   #       [29579, 23453, 24378]
   #       [65, 98, 38472, 32701, 20961]
   #       [65, 108, 101, 120]
   #       [49]   字符串1
   print(user_list)
   """
   sort的排序原理：转化成unicode的码点再去排序
       [ "x x x" ," x x x x x " ]
       第一个位置和第一个位置进行比较……如果前面都相同如果到后面没有里，那他比有的那个小
   """
   user_list.sort()
   print(user_list)
   

   注意：排序时内部元素无法进行比较时，程序会报错（尽量数据类型统一）。【布尔类型和整数是可以比较的，但是字符串和整数是无法比较】

   #如何获取Unicode标识
   data = "王宝强"
   data_list = []
   for char in data:
       v1 = ord(char)#29579(10进制标识)
       data_list.append(v1)
   print(data)
   print(data_list)
   

9. 反转原列表

   user_list = ["王宝强","陈羽凡","Alex","贾乃亮","Alex"]
   user_list.reverse()
   
   print(user_list)
   

1.3 公共功能

1. 相加，两个列表相加获取生成一个新的列表。

   data = ["赵四","刘能"] + ["宋晓峰","范德彪"]
   print(data) # ["赵四","刘能","宋晓峰","范德彪"]
   
   v1 = ["赵四","刘能"]
   v2 = ["宋晓峰","范德彪"]
   v3 = v1 + v2
   print(v3) # ["赵四","刘能","宋晓峰","范德彪"]
   

2. 相乘，列表*整型 将列表中的元素再创建N份并生成一个新的列表。

   data = ["赵四","刘能"] * 2
   print(data) # ["赵四","刘能","赵四","刘能"]
   
   v1 = ["赵四","刘能"]
   v2 = v1 * 2
   print(v1) # ["赵四","刘能"]
   print(v2) # ["赵四","刘能","赵四","刘能"]
   

3. 运算符in包含
   由于列表内部是由多个元素组成，可以通过in来判断元素是否在列表中。

   user_list = ["狗子","二蛋","沙雕","alex"] 
   result = "alex" in user_list
   # result = "alex" not in user_list
   print(result) #  True
   
   if "alex" in user_list:
       print("在，把他删除")
       user_list.remove("alex")
   else:
       print("不在")
   

   user_list = ["狗子","二蛋","沙雕","alex"] 
   if "alex" in user_list:
       print("在，把他删除")
       user_list.remove("alex")
   else:
       print("不在")
   
   text = "打倒小日本"
   data = "日" in text
   

   # 案例
   user_list = ["狗子","二蛋","沙雕","alex"] 
   if "alex" in user_list:
       print("在，把他删除")
       user_list.remove("alex")
   else:
       print("不在")
   

   # 案例
   user_list = ["王宝强","陈羽凡","Alex","贾乃亮","Alex"]
   if "Alex" in user_list:
   	index = user_list.index("Alex")
   	user_list.pop(index)
   

   # 案例：敏感词替换
   text = input("请输入文本内容：") # 按时打发第三方科技爱普生豆腐啊；了深刻的房价破阿偶打飞机
   forbidden_list = ["草","欧美","日韩"]
   for item in forbidden_list:
       text = text.replace(item,"**")
   print(text)
   

   注意：列表检查元素是否存在时，是采用逐一比较的方式，效率会比较低。

4. 获取长度

   user_list = ["范德彪","刘华强",'尼古拉斯赵四']
   print( len(user_list) )
   

5. 索引，一个元素的操作

   # 读
   user_list = ["范德彪","刘华强",'尼古拉斯赵四']
   print( user_list[0] )
   print( user_list[2] )
   print( user_list[3] ) # 报错
   

   # 改
   user_list = ["范德彪","刘华强",'尼古拉斯赵四']
   user_list[0] = "武沛齐"
   print(user_list) # ["武沛齐","刘华强",'尼古拉斯赵四']
   

   # 删
   user_list = ["范德彪","刘华强",'尼古拉斯赵四']
   del user_list[1]  #只能删除，但是拿不到这个值
   
   user_list.remove("刘华强")  #也是删除
   ele = user_list.pop(1)   #不光可以删除还可以拿到这个值
   

   注意：超出索引范围会报错。
   提示：由于字符串是不可变类型，所以他只有索引读的功能，而列表可以进行 读、改、删

6. 切片，多个元素的操作（很少用）

   # 读
   user_list = ["范德彪","刘华强",'尼古拉斯赵四']
   
   print( user_list[0:2] ) # ["范德彪","刘华强"]
   print( user_list[1:] )
   print( user_list[:-1] )
   

   # 改  批量改
   user_list = ["范德彪", "刘华强", '尼古拉斯赵四']
   user_list[0:2] = [11, 22, 33, 44]
   print(user_list) # 输出 [11, 22, 33, 44, '尼古拉斯赵四']
   
   user_list = ["范德彪", "刘华强", '尼古拉斯赵四']
   user_list[2:] = [11, 22, 33, 44]
   print(user_list) # 输出 ['范德彪', '刘华强', 11, 22, 33, 44]
   
   user_list = ["范德彪", "刘华强", '尼古拉斯赵四']
   user_list[3:] = [11, 22, 33, 44]
   print(user_list) # 输出 ['范德彪', '刘华强', '尼古拉斯赵四', 11, 22, 33, 44]
   
   
   user_list = ["范德彪", "刘华强", '尼古拉斯赵四']
   user_list[10000:] = [11, 22, 33, 44]
   print(user_list) # 输出 ['范德彪', '刘华强', '尼古拉斯赵四', 11, 22, 33, 44]
   
   
   user_list = ["范德彪", "刘华强", '尼古拉斯赵四']
   user_list[-10000:1] = [11, 22, 33, 44]
   print(user_list) # 输出 [11, 22, 33, 44, '刘华强', '尼古拉斯赵四']
   

   # 删
   user_list = ["范德彪", "刘华强", '尼古拉斯赵四']
   del user_list[1:]
   print(user_list) # 输出 ['范德彪']
   

7. 步长

   user_list = ["范德彪","刘华强",'尼古拉斯赵四',"宋小宝","刘能"]
   #              0        1        2          3       4
   print( user_list[1:4:2] )
   print( user_list[0::2] )
   print( user_list[1::2] )
   print( user_list[4:1:-1] )#“刘能” "宋小宝" "尼古拉斯赵四"
   

   # 案例：实现列表的翻转
   user_list = ["范德彪","刘华强",'尼古拉斯赵四',"宋小宝","刘能"]
   new_data = user_list[::-1]
   print(new_data)
   
   
   data_list = ["范德彪","刘华强",'尼古拉斯赵四',"宋小宝","刘能"]
   data_list.reverse()
   print(data_list)
   
   # 给你一个字符串请实现字符串的翻转？
   name = "武沛齐"
   name[::-1]
   

8. for循环

   user_list = ["范德彪","刘华强",'尼古拉斯赵四',"宋小宝","刘能"]
   for item in user_list:
   	print(item)
   

   user_list = ["范德彪","刘华强",'尼古拉斯赵四',"宋小宝","刘能"]
   
   for index in range( len(user_list) ):
       item = user_index[index]
       print(item)
   

   切记，循环的过程中对数据进行删除会踩坑【面试题】。

   # 错误方式， 有坑，结果不是你想要的。
   
   user_list = ["刘的话", "范德彪", "刘华强", '刘尼古拉斯赵四', "宋小宝", "刘能"]
   for item in user_list:
       if item.startswith("刘"):
           user_list.remove(item)
           
   print(user_list)
   
   
   

   # 正确方式，倒着删除。
   user_list = ["刘的话", "范德彪", "刘华强", '刘尼古拉斯赵四', "宋小宝", "刘能"]
   for index in range(len(user_list) - 1, -1, -1):
       item = user_list[index]
       if item.startswith("刘"):
           user_list.remove(item)
   print(user_list)
   

1.4 转换

• int、bool无法转换成列表

• str

  name = "武沛齐"
  
  data = list(name)  # ["武","沛","齐"]
  print(data)
  

• 超前

  v1 = (11,22,33,44) # 元组
  vv1 = list(v1)     # 列表 [11,22,33,44]
  
  v2 = {"alex","eric","dsb"} # 集合
  vv2 = list(v2) # 列表 ["alex","eric","dsb"]
  

1.5. 其他

1.5.1 嵌套

列表属于容器，内部可以存放各种数据，所以他也支持列表的嵌套，如：

data = [ "谢广坤",["海燕","赵本山"],True,[11,22,[999,123],33,44],"宋小宝" ]

对于嵌套的值，可以根据之前学习的索引知识点来进行学习，例如：

data = [ "谢广坤",["海燕","赵本山"],True,[11,22,33,44],"宋小宝" ]

print( data[0] ) # "谢广坤"
print( data[1] ) # ["海燕","赵本山"]
print( data[0][2] ) # "坤"
print( data[1][-1] ) # "赵本山"

data.append(666)
print(data) # [ "谢广坤",["海燕","赵本山"],True,[11,22,33,44],"宋小宝",666]

data[1].append("谢大脚")
print(data) # [ "谢广坤",["海燕","赵本山","谢大脚"],True,[11,22,33,44],"宋小宝",666 ]


del data[-2]
print(data) # [ "谢广坤",["海燕","赵本山","谢大脚"],True,[11,22,33,44],666 ]


data[-2][1] = "alex"
print(data) # [ "谢广坤",["海燕","赵本山","谢大脚"],True,[11,"alex",33,44],666 ]


data[1][0:2] = [999,666]
print(data) # [ "谢广坤",[999,666,"谢大脚"],True,[11,"alex",33,44],666 ]

# 创建用户列表
#    用户列表应该长： [ ["alex","123"],["eric","666"] ]

# user_list = [["alex","123"],["eric","666"],]
# user_list.append(["alex","123"])
# user_list.append(["eric","666"])


user_list = []
while True:
    user = input("请输入用户名：")
    pwd = input("请输入密码：")

    data = []
    data.append(user)
    data.append(pwd)
    
    user_list.append(data)

user_list = []
while True:
    user = input("请输入用户名(Q退出)：")
    if user == "Q":
        break
    pwd = input("请输入密码：")
    data = [user,pwd]
    user_list.append(data)

print(user_list)