# 对于字典,它和列表、元组一样,也可以使用字典推导式来快速的生成一个字典,
# 它的表现形式和列表推导式类似,只不过将列表推导式中的中括号[]改为大括号{}:
# {键表达式:值表达式 for 循环}
# 1 2 3 4 平方
# dict01 = {}
# for item in range(1,11):
# dict01[item] =item ** 2
# print(dict01)
# dict01={item:item**2 for item in range(1,11)}
# print(dict01)
# 练习:[海绵宝宝,派大星,蟹老板]
# [海绵宝宝:4,派大星:3,蟹老板:3]
# list01 = ["海绵宝宝","派大星","蟹老板"]
# dict01 = {}
# for item in list01:
# dict01[item] = len(item)
# print(dict01)
# dict02={item:len(item) for item in list01}
# print(dict02)
# 练习:[海绵宝宝,派大星,蟹老板]
# [海绵宝宝:101,派大星:102,蟹老板:103]
# list01 = ["海绵宝宝","派大星","蟹老板"]
# list02 = ["101","102","103"]
# dict01 = {}
# for i in range(len(list01)):
# dict01[list01[i]] = list02[i]
# print(dict01)
# dict02 = {list01[i]:list02[i] for i in range(len(list01))}
# print(dict02)
# 需求:字典如何根据value查找key
# 解决方案1:键值互换
# dict02 = {v:k for k,v in dict01.items()}
#缺点:如果key重复,则丢失数据
# dict02 = [(v:k) for k,v in dict01.items()]