Re: string concatenation: several seconds - C# Discussion Boards

Re: get type of anonymous list

2-Dec-11 9:44

Don't post to multiple forums, you have already asked this in Q&A. If the question is in multiple locations you will sort through multiple responses and people responding will not benefit from other responses in other forums and possibly give you duplicated and/or conflicting responses.

No comment

Wonde Tadesse2-Dec-11 16:48

Wonde Tadesse

2-Dec-11 16:48

Look this CodeProject Q/A.Get The type of anonymous list[^]

Wonde Tadesse
MCTS

Including an additional enum property into an object?

Goalie352-Dec-11 9:20

Goalie35

2-Dec-11 9:20

How can I assign an additional "enum" property to a pre-existing object?

I'm building a Trophy system for my website where user's can earn trophies for various achievements. I currently have a "Trophy" object which was created for me automatically in Linq when I created my dbml file. Nice and simple so far Smile | :)

Now however, I want to include an additional property to my "Trophy" object of type enum called "TrophyLevel". For several, long winded reasons, I don't want to include TrophyLevel as a part of the actual "Trophy" object. So, I've tried setting it up in a partial class like the following:

public partial class Trophy
    {
        public enum TrophyLevel
        {
            Bronze = 1,
            Silver = 2,
            Gold = 3,
            Platinum = 4
        }
    }

Is this the correct way I should be setting this up, and if so, how do I access it? So, basically, I want to be able to have code like the following:
Trophy.TrophyLevel = 1;
OR
String level = Trophy.TrophyLevel;

Am I going about this correctly?

Thanks

Re: Including an additional enum property into an object?

Not Active2-Dec-11 9:47

Re: Including an additional enum property into an object?

2-Dec-11 9:47

Yes, this is correct. EF generated a partial class for Trophy which you would extend by adding another partial class definition in the same namespace.

http://msdn.microsoft.com/en-us/library/wa80x488(v=VS.100).aspx[^]

No comment

BillWoodruff2-Dec-11 19:27

BillWoodruff

2-Dec-11 19:27

Yes, you are certainly creating a valid extension to the Trophy class via using the 'partial keyword, and I assume you realize that both the original and added classes should/must be declared with the partial keyword:

public partial class Trophy

If I assume, based on what you present here, that 'Trophy is not a static class, then you are going to be creating instances of Trophy: you'll be using the instances like this:

Trophy tp1 = new Trophy();
Trophy tp2 = new Trophy();

tp1.theTrophyLevel = Trophy.TrophyLevel.Platinum;
tp2.theTrophyLevel = Trophy.TrophyLevel.Silver;

String level = tp1.theTrophyLevel.ToString();

"Anyone who shows me my 'blind spots' gives me the gift of sight." ... a thought from the shallows of the deeply shallow mind of ... Bill

string concatenation: several seconds

pirotrav2-Dec-11 2:35

2-Dec-11 2:35

Hi folks,

I am currently working on a side project for entertainment/ minor work related use. I am very much an entry level programmer.

The issue I am having, is I am attempting to output a series of strings with line breaks into a read only text box (user read only; I can of course access it in the code). I am storing them in a temporary string (although I also tried line by line printing), and then printing them to the labelbox. It is taking a huge ammount of time; 9 items takes .5 seconds. 200 takes several minutes. This is on an i7 2600k etc. etc (although the app is on one thread but still).

txtOutput.Clear();

StringBuilder builder = new StringBuilder();
foreach (string s in sorted)
{

builder.Append(s);
builder.Append("\r\n");

}
txtOutput.Text = builder.ToString();

}

I have pinpointed the problem to the code in bold. I have tried both stringbuilder and + concatenate. Can anyone help me improve efficiency and explain why its so slow?

Thank you,
Travis

modified 2-Dec-11 8:45am.

Rob Philpott2-Dec-11 2:43

2-Dec-11 2:43

Good question! Should be like lightning. What is 'sorted'?

Regards,
Rob Philpott.

pirotrav2-Dec-11 2:48

2-Dec-11 2:48

string[] strOutput = alFormOutput.ToArray(typeof(string)) as string[];

Func<string, object=""> convert = str =>
{
try { return int.Parse(str); }
catch { return str; }
};
var sorted = strOutput.OrderBy(
str => Regex.Split(str.Replace(" ", ""), "([0-9]+)").Select(convert),
new sortAlg.EnumerableComparer<object>());

Part of this I borrowed from another document, but to my understanding sorted is an array of strings. Before I send it to the 'sort' (where all of the above code and previous code posted is located) function, it is an arrayList. Do note that the sorting itself takes probably only a second on several hundred items. I tested that with timers and it was not the issue. Wish I could answer better, but I only partially understand natural sort.

Here is the article the code above is based on.
http://www.interact-sw.co.uk/iangblog/2007/12/13/natural-sorting[^]

scroll to the bottom.

appreciate the quick reply

Rob Philpott2-Dec-11 2:51

2-Dec-11 2:51

Ah, well 'sorted' isn't a simple collection, its an IEnumerable which means in you foreach loop it will actually go away for each iteration and do all that sorting stuff. The Regex in the middle of it all is probably responsible.

Make sense? The thing you're iterating over isn't sorted, it gets sorted with each iteration.

Regards,
Rob Philpott.

pirotrav2-Dec-11 2:57

2-Dec-11 2:57

I get the general sense of what your saying. Will have to research this ienumerator business. So is 'sorted' somehow calling class related sorting functions every time it is concatened?

Additionally, is there a better way to do a natural sort? Also Cint is off limits, as mixed letters and numeric characters is quite possible. And finally, is this a memory transfer issue? Processor is about dead while all of this is going on.

Really appreciate the good info.

~Travis

Rob Philpott2-Dec-11 3:13

2-Dec-11 3:13

Pretty much. sorted is not an array, its an IEnumerable class which has basic 'get next' functionality. The foreach calls the get next which calls the RegEx stuff.

Without intense study, I can't see what the sorting algorithm is trying to do. Call me old fashioned, but put everything in an array, create an IComparer and sort the array using Array.Sort with that.

Sorry, I can see no reason why the CPU would idle while you wait for this.

Regards,
Rob Philpott.

BobJanova2-Dec-11 5:49

BobJanova

2-Dec-11 5:49

That isn't true unless OrderBy is really, really dumb. It should create an order vector which the enumerator will then read sequentially.

Rob Philpott2-Dec-11 5:55

2-Dec-11 5:55

Fair dos. So why does it take so long to execute then?

Regards,
Rob Philpott.

BobJanova2-Dec-11 6:05

BobJanova

2-Dec-11 6:05

If I knew that I'd have posted a reply directly under the OP Confused | :confused:

Not Active2-Dec-11 3:01

2-Dec-11 3:01

First off please use the correct formatting when posting code snippets to make it easier to read. Use the "code" toolbar item above the textbox when entering your question/response.

If all you are doing is iterating through the string array to insert a separator you could use the String.Join[^] method

string withSeperators = String.Join("/r/n", sorted);

However, with very few items in the array the StringBuilder method should be faster than you have indicated.

No comment

pirotrav2-Dec-11 3:13

2-Dec-11 3:13

Tried the join method. It actually took quite a bit longer than the builder one. I think the processing time has to do with the class I attached in the link in my 3rd post. Apparently the methods in that class are called upon when concatenating 'sorted' with "\r\n" (didn't even know that was possible to tell the truth).

Anyone know of a better natural sort, or am I maybe implementing it wrong?
Can I convert 'sorted' (ienumerator type) to a string[] somehow, and then append based on that copy?

If anyone can help demystify the best approach to a natural sort that would be great.

Appreciate all the help guys. I'm off to school, so I won't reply for some time most likely.

~Travis

Not Active2-Dec-11 4:04

2-Dec-11 4:04

Perhaps this will help Numeric String Sort in C#[^]

No comment

emardini2-Dec-11 3:34

emardini

2-Dec-11 3:34

Try changing your Func:

Func<string, object> convert = str =>
            {
                int value = 0;
                return int.TryParse(str, out value) ?  (object)value : str;
            };

That could fix your problem.

pirotrav2-Dec-11 21:03

2-Dec-11 21:03

Emardini,

Tried your code. Worked like a dream. That said, this part of the program was borrowed from the link above, so I never really understood it in the first place. I have gone from several minute sorts to < 1 second.

  Func<string, object> convert = str =>
  {
      try { return int.Parse(str); }
      catch { return str; }
 };//My function (one borrowed from link above)

Func<string, object> convert = str =>
{
    int value = 0;
    return int.TryParse(str, out value) ? (object)value : str;
};//Emardini's function that works 'properly', i.e fast

Emardini, or anyone else. Can you break this down and explain what the difference/ meaning of both functions is? I know that sounds silly since it's from my program, but this project is merely to polish up on what I learned in previous semesters, complete a mundane task, and learn as much as possible along the way.

Edit:Having looked at this a bit more, if I understand right 'out' vs 'return' is the key difference. Still not entirely sure on what that means in the context of the above code.

modified 3-Dec-11 3:15am.

Gerry Schmitz2-Dec-11 22:23

Gerry Schmitz

2-Dec-11 22:23

The simple fact is that "exception handling" (the "try...catch" block) is very "expensive" in terms of overhead; what with "stack unwinding", etc.

"try ... catch" blocks are for "exceptional" conditions; not for performing "data validation" (i.e. instead of "TryParse").

pirotrav3-Dec-11 19:26

3-Dec-11 19:26

Great answer. Thanks a lot to everyone that replied to this thread. Really great info!! Learned a lot, and it works great too.

~Travis

PIEBALDconsult2-Dec-11 3:48

PIEBALDconsult

2-Dec-11 3:48

Other minor points:

Try AppendFormat rather than two Appends.

And try pre-alloctaing the StringBuilder --

StringBuilder builder = new StringBuilder(txtOutput.Text.Length);

(before clearing the TextBox)

OriginalGriff2-Dec-11 4:14

OriginalGriff

2-Dec-11 4:14

If "sorted" is as you say an array of strings, why faff with it at all?

txtOutput.Lines = sorted;

I just tried your code and mine:

string[] data = File.ReadAllLines(@"D:\Temp\MyLargeTextFile.txt");
Stopwatch s1 = new Stopwatch();
Stopwatch s2 = new Stopwatch();
s1.Start();
textBox1.Lines = data;
s1.Stop();
s2.Start();
StringBuilder sb = new StringBuilder();
foreach (string s in data)
    {
    sb.Append(s);
    sb.Append("\r\n");
    }
textBox2.Text = sb.ToString();
s2.Stop();
Console.WriteLine("{0} lines: {1}/{2}", data.Length,s1.Elapsed, s2.Elapsed);

The output I get is nothing like yours:

22777 lines: 00:00:01.5580246/00:00:01.5555734

How did you time your operations?

Ideological Purity is no substitute for being able to stick your thumb down a pipe to stop the water