Develop Reference

counting a string with special characters in a string in c#

I would like to count a string (search term) in another string (logfile).
Splitting the string with the method Split and searching the array afterwards is too inefficient for me, because the logfile is very large.
In the net I found the following possibility, which worked quite well so far. However,
count = Regex.Matches(_editor.Text, txtLookFor.Text, RegexOptions.IgnoreCase).Count;
I am now running into another problem there, that I get the following error when I count a string in the format of "Nachricht erhalten (".
Errormessage:
System.ArgumentException: "Nachricht erhalten (" analysed - not enough )-characters.

You need to escape the ( symbol as it has a special function in regular expressions:
var test = Regex.Matches("Nachricht erhalten (3)", #"Nachricht erhalten \(", RegexOptions.IgnoreCase).Count;
If you do this by user input where the user is not familiar with regular expressions you probably easier off using IndexOf in a while loop, where you keep using the new index found in the last loop. Which might also be a bit better on performance than a regular expression. Example:
var test = "This is a test";
var searchFor = "is";
var count = 0;
var index = test.IndexOf(searchFor, 0);
while (index != -1)
{
++count;
index = test.IndexOf(searchFor, index + searchFor.Length);
}

Resolving File Name Permutations

I am attempting to import a .CSV file into my database which is a table export from an image management system. This system allows end-users to take images and (sometimes) split them into multiple images. There is a column in this report that signifies the file name of the image that I am tracking. If items are split in the image management system, the file name receives an underscore ("_") on the report. The previous file name is not kept. The way the items can possibly exist on the CSV are shown below:
Report 1 # 8:00AM: ABC.PNG
Report 2 # 8:30AM: ABC_1.PNG
ABC_2.PNG
Report 3 # 9:00AM: ABC_1_1.PNG
ABC_1_2.PNG
ABC_2_1.PNG
ABC_2_2.PNG
Report 4 # 9:30AM ABC_1_1_1.PNG
ABC_1_1_2.PNG
ABC_1_2.PNG
ABC_2_1.PNG
ABC_2_2.PNG
I am importing each file name into its own record. When an item is split, I would like to identify the previous version and update the original record, then add the new split record into my database. The key to knowing if an item is split is locating an underscore ("_").
I am not sure what I should do to recreate previous child names, I have to test every previous iteration of the file name to see if it exists. My problem is interpreting the current state of the file name and rebuilding all previous possibilities. I do not need the original name, only the first possible split name up until the current name. The code below shows kind of what I am getting at, but I am not sure how to do this cleanly.
String[] splitName = theStringToSplit.Split('_');
for (int i = 1; i < splitName.Length - 1; i++)
{
//should concat everything between 0 and i, not just 0 and I
//not sure if this is the best way or what I should do
MessageBox.Show(splitName[0] + "_" + splitName[i] + ".PNG");
}

The thing you are looking for is part of string.
So string.Join() might help you joining an array to a delimited string:
It also contains a parameter start index and number of items to use.
string[] s = new string[] { "2", "a", "b" };
string joined = string.Join("_", s, 0 ,3);
// joined will be "2_a_b"
Maybe you are using the wrong tool for you problem. If you want to keep the last "_", you may want to use LastIndexOf() or even Regular Expressions. Anyways: You should not unnecessarily rip of names and re-glue them. If done, do it cultrue invariant and not culture specific (there might be different interpretations of "-" or the low letter of "I".
string fnwithExt = "Abc_12_23.png";
string fn = System.IO.Path.GetFileName(fnwithExt);
int indexOf = fn.LastIndexOf('_');
string part1 = fn.Substring(0, indexOf-1);
string part2 = fn.Substring(indexOf+1);
string part3 = System.IO.Path.GetExtension(fnwithExt);
string original = System.IO.Path.ChangeExtension(part1 + "_"+ part2, part3);

Calculating number of words from input text

I split the input paragraph by . and store it in an array like this:
string[] totalSentences = inputPara.Split('.')
then the function below is called which calculates total number of Words from each sentence like this:
public void initParaMatrix()
{
int size = 0;
for (int i = 0; i < totalSentences.Length; i++)
{
string[] words = totalSentences[i].Split();
size = size + words.Length;
//rest of the logic here...
}
matrixSize = size;
paraMatrix = new string[matrixSize, matrixSize];
}
paraMatrix is a 2D matrix equal to length of all words which I need to make in my logic.
The problem here is when I input only one sentence which has 5 words, the size variable gets the value 7. I tried the debugger and I was getting total of 2 sentences instead of 1.
Sentence 1. "Our present ideas about motion." > this is actual sentence which have only 5 words
Sentence 2. " " > this is the exact second sentence I'm getting.
Here is the screenshot:
Why I'm getting two sentences here and how is size getting value 7?

This makes perfect sense. If the second sentence has nothing but a " ", and you split along the " ", then you'll have two empty strings as a result. The easiest thing to do here is change the line you do the split, and add a trim:
string[] words = totalSentences[i].Trim().Split();
I don't know what version of Split that you're using since it accepts no parameters, but if you use String.Split you can set the second parameter so that empty entries are automatically removed by using the option StringSplitOptions.RemoveEmptyEntries.

You're not resetting the size integer to zero. So that's why you get 7 for the second sentence.
For the second sentence, which is a space, try inputPara.Trim() which should remove the space at the end of the string.

How to replace text within a string based on their indices

I have a string of text coming from a database. I also have a list of links from a database which have a start index and length correstponding to my string. I want to append the links within the text to be links
<a href=...
I.e
var stringText = "Hello look at http://www.google.com and this hello.co.uk";
This would have in the database
Link:http://www.google.com
Index:14
Length:21
Link:hello.co.uk
Index:45
Length:11
I eventually want
var stringText = "Hello look at http://www.google.com and this hello.co.uk";
There may be many links in the string, so I need a way of looping through these links and replacing based on the index and length. I would just loop through and replace based on the link (string.replace) but causes issues if there are the same link twice
var stringText = "www.google.com www.google.com www.google.com";
www.google.com would become a link and the second time would make the link within the link... a link.
I can obviously find the first index, but if I change it at that point, the index's are no longer valid.
Is there an easy way to do this or am I missing something?

You simply need to remove the subject from source using String.Remove, then use String.Insert to insert your replacement string.
As #hogan suggested in comments you need to sort the replacement list and do the replacement in reverse order (from last to first) to make it work.
If you need to perform many replacements in single string I recommend StringBuilder for performance reasons.

I would use regural expressions.
Take a look at this: Regular expression to find URLs within a string
It might help.

Here's solution without Remove or Insert, or regexes. Just addition.
string stringText = "Hello look at http://www.google.com and this hello.co.uk!";
var replacements = new [] {
new { Link = "http://www.google.com", Index = 14, Length = 21 },
new { Link = "hello.co.uk", Index = 45, Length = 11 } };
string result = "";
for (int i = 0; i <= replacements.Length; i++)
{
int previousIndex = i == 0 ? 0 : replacements[i - 1].Index + replacements[i - 1].Length;
int nextIndex = i < replacements.Length ? replacements[i].Index : replacements[i - 1].Index + replacements[i - 1].Length + 1;
result += stringText.Substring(previousIndex, nextIndex - previousIndex);
if (i < replacements.Length)
{
result += String.Format("{1}", replacements[i].Link,
stringText.Substring(replacements[i].Index, replacements[i].Length));
}
}

String Find & Replace Method

I need to locate a specific part of a string value like the one below, I need to alter the "Meeting ID" to a specific number.
This number comes from a dropdownlist of multiple numbers, so I cant simply use find & replace. As the text could change to one of multiple numbers before the user is happy.
The "0783," part of the string never changes, and "Meeting ID" is always followed by a ",".
So i need to get to "0783, INSERT TEXT ," and then insert the new number on the Index Changed event.
Here is an example :-
Business Invitation, start time, M Problem, 518-06-xxx, 9999 999
0783, Meeting ID, xxx ??
What is the best way of locating this string and replacing the test each time?
I hope this makes sense guys?

Okay, so there are several ways of doing this, however this seems to be a string you have control over so I'm going to say here's what you want to do.
var myString = string.Format("Business Invitation, start time, M Problem, 518-06-xxx, 9999 999 0783, {0}, xxx ??", yourMeetingId);
If you don't have control over it then you're going to have to be a bit more clever:
var startingIndex = myString.IndexOf("0783, ");
var endingIndex = myString.IndexOf(",", startingIndex + 6);
var pattern = myString.Substring(startingIndex + 6, endingIndex - (startingIndex + 6));
myString = myString.Replace(pattern, yourMeetingId);

You should store your "current" Meeting ID in a variable, changing it along with your user's actions, and then use that same global variable whenever you need the string.
This way, you don't have to worry about what's inside the string and don't need to mess with array indexes. You will also be safe from magic numbers / strings, which are bound to blow up in your face at some point in the future.

You can try with Regex.Replace method
string pattern = #"\d{3},";
Regex regex = new Regex(pattern);
var inputStr = "518-06-xxx, 9999 999 0783";
var replace = "..."
var outputStr = regex.Replace(inputStr, replace);

use Regex.Split by token "0783," then in the second string in the array return split by token "," the first element in the string array would be where you would insert new text. Then use string.Join to join the first split with "0783," and the join the second with ",".
string temp = "Business Invitation, start time, M Problem, 518-06-xxx, 9999 999 0783, Meeting ID, xxx ??";
string newID = "1234";
string[] firstSplits = Regex.Split(temp, "0783,");
string[] secondSplits = Regex.Split(firstSplits[1], ",");
secondSplits[0] = newID;
string #join = string.Join(",", secondSplits);
firstSplits[1] = #join;
string newString = string.Join("0783,", firstSplits);