A simplified version of what you're doing. Instead of using SubString or IndexOf, I split the input into a list of strings, and remove the items that contain a URL. I iterate over the list in reverse as removing an item in a forward loop direction will skip an index.
public static string RemoveUrl(string input)
{
List<string> words = input.Split(" ").ToList();
for (int i = words.Count - 1; i >= 0; i--)
{
if (words[i].StartsWith("https://")) words.RemoveAt(i);
}
return string.Join(" ", words);
}
This methods advantage is avoiding SubString and Replace methods that essentially create new Strings each time they're used. In a loop this excessive string manipulation can put pressure on the Garbage Collector and bloat the Managed Heap. A Split and Join has less performance cost in comparison especially when used in a loop like this with a lot of data.
@Moshi is correct with large amounts of data, so this is more of a Production Code Base example:
public static class Ext
{
public static LinkedList<T> RemoveAll<T>(this LinkedList<T> list, Predicate<T> match)
{
if (list == null)
{
throw new ArgumentNullException("list");
}
if (match == null)
{
throw new ArgumentNullException("match");
}
var count = 0;
var node = list.First;
while (node != null)
{
var next = node.Next;
if (match(node.Value))
{
list.Remove(node);
count++;
}
node = next;
}
return list;
}
}
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
var s= "I saw a https://www.youtube.com/cat and a https://www.youtube.com/horse on https://www.youtube.com/";
//Uncomment for second run
//s= @"I saw a https://www.youtube.com/cat and a https://www.youtube.com/horse on https://www.youtube.com/
//but it doesnt work
//what I want to achieve is remove the entire https://www.youtube.com/ and display I saw a cat and a horse on
//I also want to display a message like the sentence you input doesn't have url if the sentence doesn't have any url. but as you can I didnt put any code to do that I just need to fix this code first but if you want to help me do that too, I gladly appreciated it.
//thanks for responses.";
Stopwatch watch = new Stopwatch();
watch.Start();
var resultList = RemoveUrl(s);
watch.Stop(); Debug.WriteLine(watch.Elapsed.ToString());
watch.Reset(); watch.Start();
var wordsLL = new LinkedList<string>(s.Split(' '));
var result = string.Join(' ', wordsLL.RemoveAll(x => x.StartsWith("https://")));
watch.Stop(); Debug.WriteLine(watch.Elapsed.ToString());
}
}
var s one line:
watch.Elapsed = {00:00:00.0116388}
watch.Elapsed = {00:00:00.0134778}
var s multilines:
watch.Elapsed = {00:00:00.0013588}
watch.Elapsed = {00:00:00.0009252}
