c# - string search - indexof too slow

[borked technique]

Is there a fast way to search for a string in c#? or at least be able to use ststr from c? I have to go through a humongo loop and it takes forever with indexof.

[John Veteran]

What's your loop look like? What makes you think IndexOf() is slowing you down?

[THE BAT]

  John said:

What makes you think IndexOf() is slowing you down?

Yes, why you think that ?

[gigapixels Veteran]

IndexOf() is pretty standard as far as I've seen.

I too would like to know why you think it's slowing you down...

[azcodemonkey]

  borked technique said:

Is there a fast way to search for a string in c#? or at least be able to use ststr from c? I have to go through a humongo loop and it takes forever with indexof.

Is your string made up of multiple words? Does it change much?

You could split the words out into an array, do a sort on it, and then use the BinarySearch feature of the Array object to find your word. It really depends on the string you are searching. If it doesn't change much, then cache the split and sorted string array for searching. If the string changes a lot, then it might be faster to use this approach over the loop/indexOf, but I've never done a timed comparison.

[borked technique]

i was reading a 600 mb text file. Reading a line and using indexof to see if the line contained a string took over two and a half minutes at full CPU. I wrote my own comparison and it took 15 seconds at 70% CPU.

[_kane81]

could you post your code for your comparison function.

[John Veteran]

Well I don't even want to imagine what kind of performance a 600 mb string object would have. Split it up if you can (Y)

But since you say you've created something to do it in 15 seconds, you've caught my attention; what did you do?

[borked technique]

I use a streamreader and streamwriter to read a line of text and write a line of text. I do a ToCharArray() on the string i am searching for and searching in before calling my search. Code below:

public void searchString(char[] sfor, char[] sin)

{

int i = 0;

int j = 0;

found = 0;

while (j < sin.Length - sfor.Length + 1)

{

if (i == sfor.Length)

{

found = 1;

break;

}

if (sfor == sin)

{

i++;

}

else

{

j++;

i = 0;

}

}

}

[Antaris Veteran]

Don't forget, I think IndexOf() is a linear search algorithm, so the time it takes to find the data is comparable to the length of the data you are entering.

[borked technique]

My code is pretty much linear as well.