graphene-python学习笔记（4）lists and non-null

三、列表和非空

1、NonNull

Object types, scalars, 和enums是我们在Graphene中可以定义的所有类型.在使用这些类型的时候我们可以使用其他类型修饰这些类型便于验证我们定义的类型。如：

import graphene

class Character(graphene.ObjectType):
    name = graphene.NonNull(graphene.String)

　　使用graphene.NonNull修饰graphene.String使得name代表非空的字符串字段。

上面的示例也可以这样写

import graphene

class Character(graphene.ObjectType):
    name = graphene.String(required=True)

　　2、List

import graphene

class Character(graphene.ObjectType):
    appears_in = graphene.List(graphene.String)

　　同NonNull,List将要求appers_in返回一个列表。

3、NonNull和List结合使用

import graphene

class Character(graphene.ObjectType):
    appears_in = graphene.List(graphene.NonNull(graphene.String))

　　等价于

type Character {
    appearsIn: [String!]
}