StringBuilder问题 [英] StringBuilder question

问题描述

假设我们已经定义了StringBuilder myBuilder，以下哪个是最贵的：


//方案1

myBuilder.Append（" test" +" test" +" test"）;


//场景2

myBuilder.Append（" test"）;

myBuilder.Append（" test"）;

myBuilder.Append（" test"）;

Assuming we''ve defined StringBuilder myBuilder, which of the following is most expensive:

//scenario 1
myBuilder.Append("test" + "test" + "test");

//scenario 2
myBuilder.Append("test");
myBuilder.Append("test");
myBuilder.Append("test");

推荐答案

Jerry，


你的意思是更多的线路价格昂贵？还是性能？


我想说正确的方法可能是这样的。
myBuilder.Append（" test"）。 （test1）。追加（t est2）;


Shak。

Jerry <济*** @ discussions.microsoft.com>在消息中写道

news：24 ********************************** @ microsof t.com ...

Jerry,

you mean more number of lines as expensive? or the performance?

I would say the correct way to do that may be

myBuilder.Append("test").Append("test1").Append("t est2");

Shak.
"Jerry" <Je***@discussions.microsoft.com> wrote in message
news:24**********************************@microsof t.com...

假设我们已经定义了StringBuilder myBuilder，以下哪个是
最贵的：
//场景1
myBuilder.Append （测试+测试+测试）;

//方案2
myBuilder.Append（" test"）;
myBuilder.Append （test）;
myBuilder.Append（" test"）;

Assuming we''ve defined StringBuilder myBuilder, which of the following is most expensive:
//scenario 1
myBuilder.Append("test" + "test" + "test");

//scenario 2
myBuilder.Append("test");
myBuilder.Append("test");
myBuilder.Append("test");

场景1，因为字符串的新副本正在为每个+

操作创建（这就是为什么首先有一个StringBuilder类）。


然而，这是可能的（因为常量折叠）实际上可能是
编译成myBuilding.Append（testtesttest）;,在这种情况下，第二个
场景会更贵。 br />

-

John Wood

电子邮件：名字，点，姓氏，来自priorganize.com


" Jerry" <济*** @ discussions.microsoft.com>在消息中写道

news：24 ********************************** @ microsof t.com ...

scenario 1, because a new copy of the string is being created for each +
operation (which is why there is a StringBuilder class in the first place).

However, it''s possible (because of constant folding) that may actually
compile to be myBuilding.Append("testtesttest");, in which case the second
scenario would be more expensive.

--
John Wood
EMail: first name, dot, last name, at priorganize.com

"Jerry" <Je***@discussions.microsoft.com> wrote in message
news:24**********************************@microsof t.com...

假设我们已经定义了StringBuilder myBuilder，以下哪个是
最贵的：
//场景1
myBuilder.Append （测试+测试+测试）;

//方案2
myBuilder.Append（" test"）;
myBuilder.Append （test）;
myBuilder.Append（" test"）;

Assuming we''ve defined StringBuilder myBuilder, which of the following is most expensive:
//scenario 1
myBuilder.Append("test" + "test" + "test");

//scenario 2
myBuilder.Append("test");
myBuilder.Append("test");
myBuilder.Append("test");

当然，两者都比


someString =" test" +测试 +测试;


两行代码和性能。


" John Wood" < [e-mail]>在消息中写道

news：ey ************** @ tk2msftngp13.phx.gbl ...

And of course, both are more expensive than

someString = "test" + "test" + "test";

in both lines of code and performance.

"John Wood" <[e-mail]> wrote in message
news:ey**************@tk2msftngp13.phx.gbl...

方案1，因为a正在为每个+
操作创建字符串的新副本（这就是为什么在第一个
位置有一个StringBuilder类）。
然而，它是可能的（因为常量）折叠）实际上可能编译成myBuilding.Append（testtesttest）;,在这种情况下第二种情况会更贵。

-
<济*** @ discussions.microsoft.com>在消息中写道
新闻：24 ********************************** @ microsof t.com。 ..

scenario 1, because a new copy of the string is being created for each +
operation (which is why there is a StringBuilder class in the first place).
However, it''s possible (because of constant folding) that may actually
compile to be myBuilding.Append("testtesttest");, in which case the second
scenario would be more expensive.

--
John Wood
EMail: first name, dot, last name, at priorganize.com

"Jerry" <Je***@discussions.microsoft.com> wrote in message
news:24**********************************@microsof t.com...

假设我们已经定义了StringBuilder myBuilder，以下哪个

Assuming we''ve defined StringBuilder myBuilder, which of the following

最贵：

//场景1
myBuilder.Append（" test" +" test" +" test"）;

//场景2
myBuilder.Append（" test"） ;
myBuilder.Append（" test"）;
myBuilder.Append（" test"）;

//scenario 1
myBuilder.Append("test" + "test" + "test");

//scenario 2
myBuilder.Append("test");
myBuilder.Append("test");
myBuilder.Append("test");

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