也许“种类” monad在Python中 [英] Maybe "kind-of" monad in Python

问题描述

所以，在我的Python代码中有这样的东西：

company = None
country = None

person = Person.find（id = 12345）
如果人不是None：＃found
company = Company.find（person.companyId）

如果公司不是None：
country = Country。 find（company.countryId）

return（person，company，country）


阅读了Haskell monads（特别是 Maybe ）的教程后，我想知道是否可以用另一种方式编写它。

解决方案

company = country = None
try：
person = Person.find（id = 12345）
company = Company.find（person.companyId）
country = Country.find（company.countryId）
，但AttributeError：
pass＃`person`或`company`可能是None


EAFP

Trying to find a way to clean up some of my code.

So, I have something like this in my Python code:

company = None
country = None

person = Person.find(id=12345)
if person is not None: # found        
    company = Company.find(person.companyId)

    if company is not None:
         country = Country.find(company.countryId)

return (person, company, country)

Having read a tutorial on Haskell's monads (in particular Maybe), I was wondering if it's possible to write it in another way.

解决方案

company = country = None
try:
    person  =  Person.find(id=12345)
    company = Company.find(person.companyId)
    country = Country.find(company.countryId)
except AttributeError:
    pass # `person` or `company` might be None

EAFP

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