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When using indexof and substring how do i parse the right start and end indexs ? And how do i encode hebrew chars?

I have this code:
string firstTag = "Forums2008/forumPage.aspx?forumId=";
string endTag = "</a>";
index = forums.IndexOf(firstTag, index1);
if (index == -1)
continue;
var secondIndex = forums.IndexOf(endTag, index);
result = forums.Substring(index + firstTag.Length + 12, secondIndex - (index + firstTag.Length - 50));
The string i want to extract from is for example:
הנקה
What i want to get is the word after the title only this: הנקה
And the second problem is that when i'm extracting it i see instead hebrew some gibrish like this: ������

One powerful way to do this is to use Regular Expressions instead of trying to find a starting position and use a substring. Try out this code, and you'll see that it extracts the anchor tag's title:
var input = "הנקה";
var expression = new System.Text.RegularExpressions.Regex(#"title=\""([^\""]+)\""");
var match = expression.Match(input);
if (match.Success) {
Console.WriteLine(match.Groups[1]);
}
else {
Console.WriteLine("not found");
}
And for the curious, here is a version in JavaScript:
var input = 'הנקה';
var expression = new RegExp('title=\"([^\"]+)\"');
var results = expression.exec(input);
if (results) {
document.write(results[1]);
}
else {
document.write("not found");
}

Okay here is the solution using String.Substring() String.Split() and String.IndexOf()
String str = "הנקה"; // <== Assume this is passing string. Yes unusual scape sequence are added
int splitStart = str.IndexOf("title="); // < Where to start splitting
int splitEnd = str.LastIndexOf("</a>"); // < = Where to end
/* What we try to extract is this : title="הנקה">הנקה
* (Given without escape sequence)
*/
String extracted = str.Substring(splitStart, splitEnd - splitStart); // <=Extracting required portion
String[] splitted = extracted.Split('"'); // < = Now split with "
Console.WriteLine(splitted[1]); // <= Try to Out but yes will produce ???? But put a breakpoint here and check the values in split array
Now the problem, here you can see that i have to use escape sequence in an unusual way. You may ignore that since you are simply passing the scanning string.
And this actually works, but you cannot visualize it with the provided Console.WriteLine(splitted[1]);
But if you put a break point and check the extracted split array you can see that text are extracted. you can confirm it with following screenshot

Splitting data with inconsistent delimiters

I have these data files comming in on a server that i need to split into [date time] and [value]. Most of them are delimited a single time between time and value and between date and time is a space. I already have a program processing the data with a simple split(char[]) but now found data where the delimiter is a space and i am wondering how to tackle this best.
So most files i encountered look like this:
18-06-2014 12:00:00|220.6
The delimiters vary, but i tackled that with a char[]. But today i ran into a problem on this format:
18-06-2014 12:00:00 220.6
This complicates things a little. The easy solution would be to just add a space to my split characters and when i find 3 splits combine the first two before processing?
I'm looking for a 2nd opining on this matter. Also the time format can change to something like d/m/yy and the amount of lines can run into the millions so i would like to keep it as efficient as possible.

Yes I believe the most efficient solution is to add space as a delimiter and then just combine the first two if you get three. That is going to be be more efficient than regex.

You've got a string 18-06-2014 12:00:00 220.6 where first 19 characters is a date, one character is a separation symbol and other characters is a value. So:
var test = "18-06-2014 12:00:00|220.6";
var dateString = test.Remove(19);
var val = test.Substring(20);
Added normalization:
static void Main(string[] args) {
var test = "18-06-2014 12:00:00|220.6";
var test2 = "18-6-14 12:00:00|220.6";
var test3 = "8-06-14 12:00:00|220.6";
Console.WriteLine(test);
Console.WriteLine(TryNormalizeImportValue(test));
Console.WriteLine(test2);
Console.WriteLine(TryNormalizeImportValue(test2));
Console.WriteLine(test3);
Console.WriteLine(TryNormalizeImportValue(test3));
}
private static string TryNormalizeImportValue(string value) {
var valueSplittedByDateSeparator = value.Split('-');
if (valueSplittedByDateSeparator.Length < 3) throw new InvalidDataException();
var normalizedDay = NormalizeImportDayValue(valueSplittedByDateSeparator[0]);
var normalizedMonth = NormalizeImportMonthValue(valueSplittedByDateSeparator[1]);
var valueYearPartSplittedByDateTimeSeparator = valueSplittedByDateSeparator[2].Split(' ');
if (valueYearPartSplittedByDateTimeSeparator.Length < 2) throw new InvalidDataException();
var normalizedYear = NormalizeImportYearValue(valueYearPartSplittedByDateTimeSeparator[0]);
var valueTimeAndValuePart = valueYearPartSplittedByDateTimeSeparator[1];
return string.Concat(normalizedDay, '-', normalizedMonth, '-', normalizedYear, ' ', valueTimeAndValuePart);
}
private static string NormalizeImportDayValue(string value) {
return value.Length == 2 ? value : "0" + value;
}
private static string NormalizeImportMonthValue(string value) {
return value.Length == 2 ? value : "0" + value;
}
private static string NormalizeImportYearValue(string value) {
return value.Length == 4 ? value : DateTime.Now.Year.ToString(CultureInfo.InvariantCulture).Remove(2) + value;
}

Well you can use this one to get the date and the value.
(((0[1-9]|[12][0-9]|3[01])-(0[1-9]|1[012])-(19|20)\d\d)\s((\d{2}:?){3})|(\d+\.?\d+))
This will give you 2 matches
1º 18-06-2014 12:00:00
2º 220.6
Example:
http://regexr.com/391d3

This regex matches both kinds of strings, capturing the two tokens to Groups 1 and 2.
Note that we are not using \d because in .NET it can match any Unicode digits such as Thai...
The key is in the [ |] character class, which specifies your two allowable delimiters
Here is the regex:
^([0-9]{2}-[0-9]{2}-[0-9]{4} (?:[0-9]{2}:){2}[0-9]{2})[ |]([0-9]{3}\.[0-9])$
In the demo, please pay attention to the capture Groups in the right pane.
Here is how to retrieve the values:
var myRegex = new Regex(#"^([0-9]{2}-[0-9]{2}-[0-9]{4} (?:[0-9]{2}:){2}[0-9]{2})[ |]([0-9]{3}\.[0-9])$", RegexOptions.IgnoreCase);
string mydate = myRegex.Match(s1).Groups[1].Value;
Console.WriteLine(mydate);
string myvalue = myRegex.Match(s1).Groups[1].Value;
Console.WriteLine(myvalue);
Please let me know if you have questions

Given the provided format I'd use something like
char delimiter = ' '; //or whatever the delimiter for the specific file is, this can be set in a previous step
int index = line.LastIndexOf(delimiter);
var date = line.Remove(index);
var value = line.Substring(++index);
If there are that many lines and efficiency matters, you could obtain the delimiter once on the first line, by looping back from the end and find the first index that is not a digit or dot (or comma if the value can contain those) to determine the delimiter, and then use something such as the above.
If each line can contain a different delimiter, you could always track back to the first not value char as described above and still maintain adequate performance.
Edit: for completeness sake, to find the delimiter, you could perform the following once per file (provided that the delimiter stays consistent within the file)
char delimiter = '\0';
for (int i = line.Length - 1; i >= 0; i--)
{
var c= line[i];
if (!char.IsDigit(c) && c != '.')
{
delimiter = c;
break;
}
}

How to extract required data?

The serial data I receive is like this
AT+CMGR=3
+CMGR: "REC READ","919742400000",,"2014/01/17 22:52:44+22"
G LED ON
OK
Actually it will be like this
AT+CMGR=3\r\n\r\n+CMGR: "REC READ","919742400000",,"2014/01/17 22:52:44+22"\r\nG LED ON\r\n\r\n\r\nOK\r\n
I need to extract
3 (Message Index can have any integer value)
REC READ (Msg Status)
919742400000 (Originating Number)
2014/01/17 22:52:44+22 (Date Time Stamp)
G LED ON (Actual Message SMS)
The VC#.Net code that I have written is
Regex r = new Regex(#"\+CMGR: (\d+),""(.+)"",""(.+)"",(.*),""(.+)""\r\n(.+)\r\n");
Match m = r.Match(mySMS); //mySMS is a string and contains the above mentioned data
int Index = int.Parse(m.Groups[1].Value); //(3 in above example)
string Status = m.Groups[2].Value; //(REC READ)
string Sender = m.Groups[3].Value; //(919742400000)
string Sent = m.Groups[4].Value; //2014/01/17 22:52:44+22
string Message = m.Groups[5].Value; //G LED ON
Another thing is The actual message (SMS) can contain double quoted strings like
"G "LED" ON" and I might also be able to extract
G "LED" ON
The above VC# code is not working.
How can I use RegEx or any other method to extract the required datas?

I would say your main structure is line-based, ie you either use ReadLine() oryou split the string:
string[] lines = mySMS.Split(new string[] {"\r\n"}, StringSplitOptions.None);
Now lines[2] constians your main data, comma-separated. lines[3] is your G "LED" ON.
To parse lines[2]:
string[] parts = lines[2].Split(',');
string OriginatingNumber = parts[1];
string DateTimeStamp = parts[3];
parts[0] will hold +CMGR: "REC READ", use another Split() or break on the : some other way.

Parse multiple values from string c#

Suppose I have written "5 and 6" or "5+6". How can I assign 5 and 6 to two different variables in c# ?
P.S. I also want to do certain work if certain chars are found in string. Suppose I have written 5+5. Will this code do that ?
if(string.Contains("+"))
{
sum=x+y;
}

string input="5+5";
var numbers = Regex.Matches(input, #"\d+")
.Cast<Match>()
.Select(m => m.Value)
.ToList();

Personally, I would vote against doing some splitting and regular expression stuff.
Instead I would (and did in the past) use one of the many Expression Evaluation libraries, like e.g. this one over at Code Project (and the updated version over at CodePlex).
Using the parser/tool above, you could do things like:
A simple expression evaluation then could look like:
Expression e = new Expression("5 + 6");
Debug.Assert(11 == e.Evaluate());
To me this is much more error-proof than doing the parsing all by myself, including regular expressions and the like.

You should use another name for your string than string
var numbers = yourString.Split("+");
var sum = Convert.ToInt32(numbers[0]) + Convert.ToInt32(numbers[1]);
Note: Thats an implementation without any error checking or error handling...

If you want to assign numbers from string to variables, you will have to parse string and make conversion.
Simple example, if you have text with only one number
string text = "500";
int num = int.Parse(text);
Now, if you want to parse something more complicated, you can use split() and/or regex to get all numbers and operators between them. Than you just iterate array and assign numbers to variables.
string text = "500+400";
if (text.Contains("+"))
{
String[] data = text.Split("+");
int a = int.Parse(data[0]);
int b = int.Parse(data[1]);
int res = a + b;
}
Basicly, if you have just 2 numbers and operazor between them, its ok. If you want to make "calculator" you will need something more, like Binary Trees or Stack.

Use the String.Split method. It splits your string rom the given character and returns a string array containing the value that is broken down into multiple pieces depending on the character to break, in this case, its "+".
int x = 0;
int y = 0;
int z = 0;
string value = "5+6";
if (value.Contains("+"))
{
string[] returnedArray = value.Split('+');
x = Convert.ToInt32(returnedArray[0]);
y = Convert.ToInt32(returnedArray[1]);
z = x + y;
}

Something like this may helpful
string strMy = "5&6";
char[] arr = strMy.ToCharArray();
List<int> list = new List<int>();
foreach (char item in arr)
{
int value;
if (int.TryParse(item.ToString(), out value))
{
list.Add(item);
}
}
list will contains all the integer values

You can use String.Split method like;
string s = "5 and 6";
string[] a = s.Split(new string[] { "and", "+" }, StringSplitOptions.RemoveEmptyEntries);
Console.WriteLine(a[0].Trim());
Console.WriteLine(a[1].Trim());
Here is a DEMO.

Use regex to get those value and then switch on the operand to do the calculation
string str = "51 + 6";
str = str.Replace(" ", "");
Regex regex = new Regex(#"(?<rightHand>\d+)(?<operand>\+|and)(?<leftHand>\d+)");
var match = regex.Match(str);
int rightHand = int.Parse(match.Groups["rightHand"].Value);
int leftHand = int.Parse(match.Groups["leftHand"].Value);
string op = match.Groups["operand"].Value;
switch (op)
{
case "+":
.
.
.
}

Split function maybe is comfortable in use but it is space inefficient
because it needs array of strings
Maybe Trim(), IndexOf(), Substring() can replace Split() function

C# how to split a string backwards?

What i'm trying to do is split a string backwards. Meaning right to left.
string startingString = "<span class=\"address\">Hoopeston,, IL 60942</span><br>"
What I would do normally is this.
string[] splitStarting = startingString.Split('>');
so my splitStarting[1] would = "Hoopeston,, IL 60942</span"
then I would do
string[] splitAgain = splitStarting[1].Split('<');
so splitAgain[0] would = "Hoopeston,, IL 60942"
Now this is what I want to do, I want to split by ' ' (a space) reversed for the last 2 instances of ' '.
For example my array would come back like so:
[0]="60942"
[1]="IL"
[2] = "Hoopeston,,"
To make this even harder I only ever want the first two reverse splits, so normally I would do something like this
string[] splitCity,Zip = splitAgain[0].Split(new char[] { ' ' }, 3);
but how would you do that backwards? The reason for that is, is because it could be a two name city so an extra ' ' would break the city name.

Regular expression with named groups to make things so much simpler. No need to reverse strings. Just pluck out what you want.
var pattern = #">(?<city>.*) (?<state>.*) (?<zip>.*?)<";
var expression = new Regex(pattern);
Match m = expression .Match(startingString);
if(m.success){
Console.WriteLine("Zip: " + m.Groups["zip"].Value);
Console.WriteLine("State: " + m.Groups["state"].Value);
Console.WriteLine("City: " + m.Groups["city"].Value);
}
Should give the following results:
Found 1 match:
1. >Las Vegas,, IL 60942< has 3 groups:
1. Las Vegas,, (city)
2. IL (state)
3. 60942 (zip)
String literals for use in programs:
C#
#">(?<city>.*) (?<state>.*) (?<zip>.*?)<"

One possible solution - not optimal but easy to code - is to reverse the string, then to split that string using the "normal" function, then to reverse each of the individual split parts.
Another possible solution is to use regular expressions instead.

I think you should do it like this:
var s = splitAgain[0];
var zipCodeStart = s.LastIndexOf(' ');
var zipCode = s.Substring(zipCodeStart + 1);
s = s.Substring(0, zipCodeStart);
var stateStart = s.LastIndexOf(' ');
var state = s.Substring(stateStart + 1);
var city = s.Substring(0, stateStart );
var result = new [] {zipCode, state, city};
Result will contain what you requested.

If Split could do everything there would be so many overloads that it would become confusing.
Don't use split, just custom code it with substrings and lastIndexOf.
string str = "Hoopeston,, IL 60942";
string[] parts = new string[3];
int place = str.LastIndexOf(' ');
parts[0] = str.Substring(place+1);
int place2 = str.LastIndexOf(' ',place-1);
parts[1] = str.Substring(place2 + 1, place - place2 -1);
parts[2] = str.Substring(0, place2);

You can use a regular expression to get the three parts of the string inside the tag, and use LINQ extensions to get the strings in the right order.
Example:
string startingString = "<span class=\"address\">East St Louis,, IL 60942</span><br>";
string[] city =
Regex.Match(startingString, #"^.+>(.+) (\S+) (\S+?)<.+$")
.Groups.Cast<Group>().Skip(1)
.Select(g => g.Value)
.Reverse().ToArray();
Console.WriteLine(city[0]);
Console.WriteLine(city[1]);
Console.WriteLine(city[2]);
Output:
60942
IL
East St Louis,,

How about
using System.Linq
...
splitAgain[0].Split(' ').Reverse().ToArray()
-edit-
ok missed the last part about multi word cites, you can still use linq though:
splitAgain[0].Split(' ').Reverse().Take(2).ToArray()
would get you the
[0]="60942"
[1]="IL"
The city would not be included here though, you could still do the whole thing in one statement but it would be a little messy:
var elements = splitAgain[0].Split(' ');
var result = elements
.Reverse()
.Take(2)
.Concat( new[ ] { String.Join( " " , elements.Take( elements.Length - 2 ).ToArray( ) ) } )
.ToArray();
So we're
Splitting the string,
Reversing it,
Taking the two first elements (the last two originally)
Then we make a new array with a single string element, and make that string from the original array of elements minus the last 2 elements (Zip and postal code)
As i said, a litle messy, but it will get you the array you want. if you dont need it to be an array of that format you could obviously simplfy the above code a little bit.
you could also do:
var result = new[ ]{
elements[elements.Length - 1], //last element
elements[elements.Length - 2], //second to last
String.Join( " " , elements.Take( elements.Length - 2 ).ToArray( ) ) //rebuild original string - 2 last elements
};

At first I thought you should use Array.Reverse() method, but I see now that it is the splitting on the ' ' (space) that is the issue.
Your first value could have a space in it (ie "New York"), so you dont want to split on spaces.
If you know the string is only ever going to have 3 values in it, then you could use String.LastIndexOf(" ") and then use String.SubString() to trim that off and then do the same again to find the middle value and then you will be left with the first value, with or without spaces.

Was facing similar issue with audio FileName conventions.
Followed this way: String to Array conversion, reverse and split, and reverse each part back to normal.
char[] addressInCharArray = fullAddress.ToCharArray();
Array.Reverse(addressInCharArray);
string[] parts = (new string(addressInCharArray)).Split(new char[] { ' ' }, 3);
string[] subAddress = new string[parts.Length];
int j = 0;
foreach (string part in parts)
{
addressInCharArray = part.ToCharArray();
Array.Reverse(addressInCharArray);
subAddress[j++] = new string(addressInCharArray);
}