字典
字典由一些列键-值对构成，键值对包含在一对花括号里。键值用冒号分割，多个键值用逗号分隔。
创建字典
elist={1:"小猫",3:"小狗",5:"黄牛"}
print(type(elist))
print(elist[3]) //小狗
字典数据修改
print("=========================")
elist={1:"小猫",3:"小狗",5:"黄牛"}
print(type(elist))
print(elist[3])
#修改元素
elist[3] = "羊"
#添加元素
elist[7] = "水牛"
#删除元素
del elist[1]
for key,value in elist.items():
print(key,value)
遍历字典
print("=========================")
elist={1:"小猫",3:"小狗",5:"黄牛"}
print(type(elist))
print(elist[3])
#修改元素
elist[3] = "羊"
#添加元素
elist[7] = "水牛"
#删除元素
del elist[1]
#遍历键值
for key,value in elist.items():
print(key,value)
print("=========================")
#遍历所有键
for key in elist.keys():
print(key)
print("=========================")
#遍历所有值
for value in elist.values():
print(value)
print("=========================")