Pydantic:如果未传递任何值，如何将默认值传递给变量? [英] Pydantic: How to pass the default value to a variable if None was passed?
问题描述
如果在字段中未输入任何内容，我可以在Pydantic中设置默认值吗?
Can I make a default value in Pydantic if None is passed in the field?
我有以下代码，但在我看来，这里的验证器仅对模型的初始化有效，而对其他模型则无效.
I have the following code, but it seems to me that the validator here only works on initialization of the model and not otherwise.
我的代码:
class User(BaseModel):
name: Optional[str] = ''
password: Optional[str] = ''
email: EmailStr
@validator('name')
def set_name(cls, name):
return name or 'foo'
遇到的问题:
user = User(name=None, password='some_password', email='user@example.com')
print("Name is ", user.name)
# > 'Name is foo'
user.name = None
print("Name is ", user.name)
# > 'Name is None'
所需的输出:
user = User(name='some_name', password='some_password', email='user@example.com')
user.name = None
print("Name is ", user.name)
# > 'Name is foo'
关于如何获得所需输出的任何想法?我认为拥有getter和setter方法将有助于解决该问题.但是，我无法让他们在Pydantic模型中工作:
Any ideas on how I can obtain the desired output? I think having getters and setters will help in tackling the issue. However, I could not get them to work in a Pydantic model:
尝试实现getter和setter:
class User(BaseModel):
name: Optional[str] = ''
password: Optional[str] = ''
email: EmailStr
def get_password(self):
return self.password
def set_password(self, password):
self.password = hash_password(password)
password = property(get_password, set_password)
user = User(name='some_name', password='some_password', email='user@example.com')
# > RecursionError: maximum recursion depth exceeded
我还尝试了属性装饰器:
class User(BaseModel):
name: Optional[str] = ''
password: Optional[str] = ''
email: EmailStr
@property
def password(self):
return self._password
@password.setter
def password(self, password):
pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")
self._password = pwd_context.hash(password)
user = User(name='some_name', email='user@example.com')
user.password = 'some_password'
# > ValueError: "User" object has no field "password"
我还尝试覆盖 init :
I also tried overwriting the init:
class User(BaseModel):
name: Optional[str] = ""
password: Optional[str] = ""
email: EmailStr
def __init__(self, name, password, email):
pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")
password = pwd_context.hash(password)
super().__init__(name=name, password=password, email=email)
user = User(name="some_name", password="some_password", email='user@example.com')
print(user.password)
# > AYylwSnbQgCHrl4uue6kO7yiuT20lazSzK7x # Works as expected
user.password = "some_other_password"
print(user.password)
# > "some_other_password" # Does not work
user.password = None
print(user.password)
# > None # Does not work either
推荐答案
您需要在模型配置中启用 validate_assignment 选项:
You need to enable validate_assignment option in model config:
from typing import Optional
from pydantic import BaseModel, validator
class User(BaseModel):
name: Optional[str] = ''
password: Optional[str] = ''
class Config:
validate_assignment = True
@validator('name')
def set_name(cls, name):
return name or 'foo'
user = User(name=None, password='some_password', )
print("Name is ", user.name)
user.name = None
print("Name is ", user.name)
Name is foo
Name is foo
这篇关于Pydantic:如果未传递任何值，如何将默认值传递给变量?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
