var selection =from word inKeyWordsgroup word by word.Contains('*');
15.4 使用into进行查询延续
作用
将第一次的查询结果作为第二次查询的输入
into子句引入的范围变量成为查询剩余部分的范围变量
之前的任何范围变量不可在查询延续中使用
var selection =from word inKeyWordsgroup word by word.Contains('*')into groups
selectnew{
IsContextualKeyword = groups.key,
Items = groups
};
15.5 多个from子句
作用
可以实现笛卡儿积
也可实现SelectMany()相同的效果
var selection =from word inKeyWordsfrom number in numbers
selectnew{ word,number };var selection =from word inKeyWordsfrom character in word
select character;
15.6 join子句
var items =from person in persons
join department in departments
on person.departmentId equals department.id
selectnew{ person.name,DepartmentName=department.name};