Question

Q:

I want to get sub strings according to some sign like - .

EX:

if i have string like this :

saturday-sa-0-

and i wanna to get:

saturday

sa

0

I search and find the following method:

string substring = name.Split('-')[i];

---

my code block sample:

foreach (string name in q)
                {
                    for (int i = 0; i < 3; i++)
                    {
                        string substring = name.Split('-')[i];
                    }
                }

but i read the comments about the performance drawbacks when i have a long string ..
my question is: Is there any way to substring according to specific sign and not affect badly on the performance code?

Answer 1

First, you should execute the Split operation only once. I.e., instead of

some loop {
    ...
    string substring = name.Split('-')[i];
    ...
}

use

string[] substrings = name.Split('-');
some loop {
    ...
    string substring = substrings[i];
    ...
}

Second, don’t worry about the performance of Strint.Split too much unless

• you have a real, measurable performance problem and
• you know that String.Split is the culprit.

For example, if you have some database operation that takes 1 second, it does not really matter if the subsequent Split operation takes 0.001 or 0.002 seconds.

---

EDIT: Regarding the code in your comment: You can refactor

foreach (string name in q) {
    for (int i = 0; i < 3; i++) {
       string substring = name.Split('-')[i]; 
       // do something with substring
    }
}

to

foreach (string name in q) {
    string[] substrings = name.Split('-'); 
    for (int i = 0; i < 3; i++) {
       string substring = substrings[i]; 
       // do something with substring
    }
}