KeyError: 'date'的错误,不知道如何解决
KeyError: 'date'的错误,不知道如何解决
2.1 方法1通过in判断key是否存在
my = {"nick":"福哥","age":"35","languages":["c/c++","java","php","python","javascript"]}
if "province" in my:
print(my["province"])
2.2 方法2使用get方法判断key是否存在
my = {"nick":"福哥","age":"35","languages":["c/c++","java","php","python","javascript"]}
if my.get("province") is not None:
print(my["province"])
2.3 方法3使用get方法的第二个参数,如果目标key不存在则返回第二个参数
my = {"nick":"福哥","age":"35","languages":["c/c++","java","php","python","javascript"]}
print(my.get("province", "北京"))
print(my)
2.4 方法4使用setdefault方法的第二个参数,如果目标key不存在则返回第二个参数同时讲第二个参数写入key位置
my = {"nick":"福哥","age":"35","languages":["c/c++","java","php","python","javascript"]}
print(my.setdefault("province", "北京"))
print(my)
针对遇到KeyError的错误提示,可以采用以下措施进行解决: 1. 方法一,通过in判断key是否存在,具体操作如下:
my = {"nick":"福哥","age":"35","languages":["c/c++","java","php","python","javascript"]}
if "province" in my:
print(my["province"])
my = {"nick":"福哥","age":"35","languages":["c/c++","java","php","python","javascript"]}
if my.get("province") is not None:
print(my["province"])
my = {"nick":"福哥","age":"35","languages":["c/c++","java","php","python","javascript"]}
print(my.get("province", "北京"))
print(my)
my = {"nick":"福哥","age":"35","languages":["c/c++","java","php","python","javascript"]}
print(my.setdefault("province", "北京"))
print(my)
其中方法三和方法四返回的结果不一样,具体选择哪一种方法根据使用场景和需要来确定。 另外,还可以使用段落3中介绍的使用setdefault方法来解决KeyError的问题。具体操作如下:
t = {"a": "1", "b": "2", "c": "3"}
print(t.setdefault("d"))
print(t)
print(t.setdefault("d", "not exist"))
print(t)
以上就是针对遇到KeyError的错误提示的解决方法,根据不同的情况选择不同的方法即可。