Linq的学习之路-1

12月 11, 2012 0条评论 7,882次阅读 0人点赞

语法

查询表达式必须是from 子句的开头，以select 或 group子句结束。在这两个字句之间，可以where,orderby,join,let和其它from子句

其它

AsParallel 并行查询

Stopwatch sw = new Stopwatch();
Stopwatch sw2 = new Stopwatch(); 
var list = new List<Person>();
for (int i = 0; i < 2000000; i++)
{
  list.Add(new Person(i.ToString() + "名", "中国", i));
}
for (int i = 0; i < 2000000; i++)
{
  list.Add(new Person(i.ToString() + "名", "法国", i));
} 
sw.Start();
var cnums = list.AsParallel().Where(p => p.Address == "中国").Count();
sw.Stop();
sw2.Start();
var cnums2 = list.Where(p => p.Address == "中国").Count();
sw2.Stop();
Console.WriteLine("[para方法]查找结果:" + cnums + " 共用时:" + sw.Elapsed.TotalMilliseconds);
Console.WriteLine("[非para方法]查找结果:" + cnums2 + "共用时:" + sw2.Elapsed.TotalMilliseconds);
Console.Read();