Python 字典魔法二
#字典
#dict
#1根据序列,创建字典,并指定统一的值
#2根据key获取值,key不存在时,可以指定默认值(None)
v = dict.fromkeys(["k1","123","999"],123)
print(v)
dic = {
"k1":"v1",
"k2":"v2",
"k3":"v3"
}
v = dic.get("k1")
print(v)
# 3 删除获取值
v = dic.pop("k1")
print(dic,v)
# 随机删除
k,v = dic.popitem()
print(dic,k,v)
#4设置值
#已存在,不设置,获取当前key对应的值
#不存在,设置,获取当前key对应的值
v = dic.setdefault("k4","123")
print(dic,v)
#5更新
dic.update({"k1":"1111","k3":123})
print(dic)
dic.update(k1=123,k2=123,k3=123)
print(dic)
#字典常用方法
#keys() values() items() get() update()