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Parse a string in c# after reading first and last alphabet

I want to cut a string in c# after reading first and last alphabet.
string name = "20150910000549659ABCD000007348summary.pdf";
string result = "ABCD000007348"; // Something like this
string name = "1234 ABCD000007348 summary.pdf";
After reading 1234 "A" comes and at last "s" comes so I want "ABCD000007348"

Simply use Regex:
string CutString(string input)
{
Match result = Regex.Match(input, #"[a-zA-Z]+[0-9]+");
return result.Value;
}

Since you didn't say if it's always a timestamp at the beginning, I've instead opted to iterate over the string to find the first alphabetical character, rather than hardcoding s.Remove(0, n); where n is however many digits are in a timestamp.
string s = "20150910000549659ABCD000007348summary.pdf";
s = s.Replace("summary.pdf", String.Empty);
int firstLetter = 0;
foreach (char c in s)
{
if (Char.IsLetter(c))
{
firstLetter = s.IndexOf(c);
break;
}
}
s = s.Remove(0, firstLetter);

Get first word on every new line in a long string?

I am trying to add a leaderboard in my unity app
I have a long string as below(just an example, actual string is http pipe data from my web service, not manually stored):
string str ="name1|10|junk data.....\n
name2|9|junk data.....\n
name3|8|junk data.....\n
name4|7|junk data....."
I want to get the first word (string before the first pipe '|' like name1,name2...) from every line and store it in an array and then get the numbers (10,9,8... arter the '|') and store it in an other one.
Anyone know whats the best way to do this?

Fiddle here: https://dotnetfiddle.net/utp4HK
code below, you may want to revisit the algorithm for performance, but if that is not an issue, this will do the trick;
using System;
public class Program
{
public static void Main()
{
string str ="name1|10|junk data.....\nname2|9|junk data.....\nname3|8|junkdata.....\nname4|7|junk data.....";
foreach (var line in str.Split('\n'))
{
Console.WriteLine(line.Split('|')[0]);
}
}
}

First split by new-line characters:
string[] lines = str.Split(new string[]{Environment.NewLine }, StringSplitOptions.RemoveEmptyEntries);
Then you can use LINQ to get both arrays:
var data = lines.Select(l => l.Trim().Split('|')).Where(arr => arr.Length > 1);
string[] names = data.Select(arr => arr[0].Trim()).ToArray();
string[] numbers = data.Select(arr => arr[1].Trim()).ToArray();

Check out this link on splitting strings: http://msdn.microsoft.com/en-us/library/ms228388.aspx
You could first create an array of strings (one for each line) by splitting the long string with \n as the delimeter.
Then, you could split each line with | as the delimeter. The name would be the 0th index of the array and the number would be the 1st index of the array.

First of all, you can't have a multi line string without using verbatim string literal. With using verbatim string literal, you can split your string based on \r\n or Environment.NewLine like;
string str = #"name1|10|junk data.....
name2|9|junk data.....
name3|8|junk data.....
name4|7|junk data.....";
var array = str.Split(new []{Environment.NewLine},
StringSplitOptions.RemoveEmptyEntries);
foreach (var item in array)
{
Console.WriteLine(item.Split(new[]{"|"},
StringSplitOptions.RemoveEmptyEntries)[0].Trim());
}
Output will be;
name1
name2
name3
name4

Try this:
string str ="name1|10|junk data.....\n" +
"name2|9|junk data.....\n" +
"name3|8|junk data.....\n" +
"name4|7|junk data.....";
string[] tempArray1 = str.Split('\n');
string[] tempArray2 = null;
string[,] newArray = null;
for (int i = 0; i < tempArray1.Length; i++)
{
tempArray2 = tempArray1[i].Split('|');
if (newArray[0, 0].ToString().Length == 0)
{
newArray = new string[tempArray1.Length, tempArray2.Length];
}
for (int j = 0; j < tempArray2.Length; j++)
{
newArray[i,j] = tempArray2[j];
}
}

Extracting parts of a string c#

In C# what would be the best way of splitting this sort of string?
%%x%%a,b,c,d
So that I end up with the value between the %% AND another variable containing everything right of the second %%
i.e. var x = "x"; var y = "a,b,c,d"
Where a,b,c.. could be an infinite comma seperated list. I need to extract the list and the value between the two double-percentage signs.
(To combat the infinite part, I thought perhaps seperating the string out to: %%x%% and a,b,c,d. At this point I can just use something like this to get X.
var tag = "%%";
var startTag = tag;
int startIndex = s.IndexOf(startTag) + startTag.Length;
int endIndex = s.IndexOf(tag, startIndex);
return s.Substring(startIndex, endIndex - startIndex);
Would the best approach be to use regex or use lots of indexOf and substring to do the extracting based on te static %% characters?

Given that what you want is "x,a,b,c,d" the Split() function is actually pretty powerful and regex would be overkill for this.
Here's an example:
string test = "%%x%%a,b,c,d";
string[] result = test.Split(new char[] { '%', ',' }, StringSplitOptions.RemoveEmptyEntries);
foreach (string s in result) {
Console.WriteLine(s);
}
Basicly we ask it to split by both '%' and ',' and ignore empty results (eg. the result between "%%"). Here's the result:
x
a
b
c
d

To Extract X:
If %% is always at the start then;
string s = "%%x%%a,b,c,d,h";
s = s.Substring(2,s.LastIndexOf("%%")-2);
//Console.WriteLine(s);
Else;
string s = "v,u,m,n,%%x%%a,b,c,d,h";
s = s.Substring(s.IndexOf("%%")+2,s.LastIndexOf("%%")-s.IndexOf("%%")-2);
//Console.WriteLine(s);
If you need to get them all at once then use this;
string s = "m,n,%%x%%a,b,c,d";
var myList = s.ToArray()
.Where(c=> (c != '%' && c!=','))
.Select(c=>c).ToList();

This'll let you do it all in one go:
string pattern = "^%%(.+?)%%(?:(.+?)(?:,|$))*$";
string input = "%%x%%a,b,c,d";
Match match = Regex.Match(input, pattern);
if (match.Success)
{
// "x"
string first = match.Groups[1].Value;
// { "a", "b", "c", "d" }
string[] repeated = match.Groups[2].Captures.Cast<Capture>()
.Select(c => c.Value).ToArray();
}

You can use the char.IsLetter to get all the list of letter
string test = "%%x%%a,b,c,d";
var l = test.Where(c => char.IsLetter(c)).ToArray();
var output = string.Join(", ", l.OrderBy(c => c));

Since you want the value between the %% and everything after in separate variables and you don't need to parse the CSV, I think a RegEx solution would be your best choice.
var inputString = #"%%x%%a,b,c,d";
var regExPattern = #"^%%(?<x>.+)%%(?<csv>.+)$";
var match = Regex.Match(inputString, regExPattern);
foreach (var item in match.Groups)
{
Console.WriteLine(item);
}
The pattern has 2 named groups called x and csv, so rather than just looping, you can easily reference them by name and assign them to values:
var x = match.Groups["x"];
var y = match.Groups["csv"];

how do i delete one part of a string?

String mystring="start i dont know hot text can it to have here important=value5; x=1; important=value2; z=3;";
suggest i want to get the value of "importante" now i know how to do it with a substring, but it has 2 subistring, then how do i get, first one, and after the next? ...??
if it is not posible i want to try it... save the first. and delete since "start" until value5 for next query save the value2...
how to do any of two things?
i get the first value so...
string word = "important=";
int c= mystring.IndexOf(word);
int c2 = word.Length;
for (int i = c+c2; i < mystring.Length; i++)
{
if (mystring[i].ToString() == ";")
{
break;
}
else
{
label1.Text += mystring[i].ToString(); // c#
// label1.setText(label1.getText()+mystring[i].ToString(); //java
}
}

If you want to extract all values you could use a regex:
string input = "start i dont know hot text can it to have here important=value5; x=1; important=value2; z=3;";
Regex regex = new Regex(#"important=(?<value>\w+)");
List<string> values = new List<string>();
MatchCollection matches = regex.Matches(input);
foreach (Match match in matches)
{
string value= match.Groups["value"].Value;
values.Add(value);
}

You can save the values in an array, instead of showing them with MessageBox.
string mystring = "start i dont know hot text can it to have here important=value5; x=1; important=value2; z=3;";
string temp = mystring;
string word = "important=";
while (temp.IndexOf(word) > 0)
{
MessageBox.Show( temp.Substring(temp.IndexOf(word) + word.Length).Split(';')[0]);
temp = temp.Remove(temp.IndexOf(word), word.Length);
}

You can use 2 methods:
String.Remove()
and
String.Replace()

use regular expression, find all the match and reconstruct the string yourself.

formatting string in MVC /C#

I have a string 731478718861993983 and I want to get this 73-1478-7188-6199-3983 using C#. How can I format it like this ?
Thanks.

By using regex:
public static string FormatTest1(string num)
{
string formatPattern = #"(\d{2})(\d{4})(\d{4})(\d{4})(\d{4})";
return Regex.Replace(num, formatPattern, "$1-$2-$3-$4-$5");
}
// test
string test = FormatTest1("731478718861993983");
// test result: 73-1478-7188-6199-3983

If you're dealing with a long number, you can use a NumberFormatInfo to format it:
First, define your NumberFormatInfo (you may want additional parameters, these are the basic 3):
NumberFormatInfo format = new NumberFormatInfo();
format.NumberGroupSeparator = "-";
format.NumberGroupSizes = new[] { 4 };
format.NumberDecimalDigits = 0;
Next, you can use it on your numbers:
long number = 731478718861993983;
string formatted = number.ToString("n", format);
Console.WriteLine(formatted);
After all, .Net has very good globalization support - you're better served using it!

string s = "731478718861993983"
var newString = (string.Format("{0:##-####-####-####-####}", Convert.ToInt64(s));

LINQ-only one-liner:
var str = "731478718861993983";
var result =
new string(
str.ToCharArray().
Reverse(). // So that it will go over string right-to-left
Select((c, i) => new { #char = c, group = i / 4}). // Keep group number
Reverse(). // Restore original order
GroupBy(t => t.group). // Now do the actual grouping
Aggregate("", (s, grouping) => "-" + new string(
grouping.
Select(gr => gr.#char).
ToArray())).
ToArray()).
Trim('-');
This can handle strings of arbitrary lenghs.

Simple (and naive) extension method :
class Program
{
static void Main(string[] args)
{
Console.WriteLine("731478718861993983".InsertChar("-", 4));
}
}
static class Ext
{
public static string InsertChar(this string str, string c, int i)
{
for (int j = str.Length - i; j >= 0; j -= i)
{
str = str.Insert(j, c);
}
return str;
}
}

If you're dealing strictly with a string, you can make a simple Regex.Replace, to capture each group of 4 digits:
string str = "731478718861993983";
str = Regex.Replace(str, "(?!^).{4}", "-$0" ,RegexOptions.RightToLeft);
Console.WriteLine(str);
Note the use of RegexOptions.RightToLeft, to start capturing from the right (so "12345" will be replaced to 1-2345, and not -12345), and the use of (?!^) to avoid adding a dash in the beginning.
You may want to capture only digits - a possible pattern then may be #"\B\d{4}".

string myString = 731478718861993983;
myString.Insert(2,"-");
myString.Insert(7,"-");
myString.Insert(13,"-");
myString.Insert(18,"-");

My first thought is:
String s = "731478718861993983";
s = s.Insert(3,"-");
s = s.Insert(8,"-");
s = s.Insert(13,"-");
s = s.Insert(18,"-");
(don't remember if index is zero-based, in which case you should use my values -1)
but there is probably some easier way to do this...

If the position of "-" is always the same then you can try
string s = "731478718861993983";
s = s.Insert(2, "-");
s = s.Insert(7, "-");
s = s.Insert(12, "-");
s = s.Insert(17, "-");

Here's how I'd do it; it'll only work if you're storing the numbers as something which isn't a string as they're not able to be used with format strings.
string numbers = "731478718861993983";
string formattedNumbers = String.Format("{0:##-####-####-####-####}", long.Parse(numbers));
Edit: amended code, since you said they were held as a string in your your original question