创建新的变量C＃

Question

Let say I want to use

str.Split[' '].ElementAt(0) 10 times in my method.

Should I create a string variable called strSplit or just keep using str.Split[' '].ElementAt(0)? Is there a performance issue?

Answer 1

Use the entire returned array, not just the first element each time (unless you really only want the first element, and none of the others):

var result = str.Split(" ");

foreach (var splitValue in result)
{
    // do something with splitValue
}

Answer 2

Memory is cheap. Really cheap.

So are CPU cycles.

Your current method will consume less memory (more while each call to Split has not been GC'd, but you don't store the result) by a tiny amount. It will consume far more CPU cycles though, especially because the GC has to collect all the temp variables created by Split . In reality, its not going to matter. You won't see the performance difference.

For good practice, store it off in a variable. The memory used will be inconsequential, and your code will be much cleaner and more efficient (even if you don't see it!)