Develop Reference

How to replace a particular character from string in c#?

I have a string like AX_1234X_12345_X_CXY, I want to remove X from after the first underscore _ i.e. from 1234X to 1234. So final output will be like AX_1234_12345_X_CXY. How to do it?? If I use .Replace("X", "") it will replace all X which I don't want

You can iterate trough the string from the first occurrence of '_' .
you can find the first occurrence of '_' using IndexOf().
when loop will get to 'X' it will not append it to the "fixed string".
private static void Func()
{
string Original = "AX_1234X_12345_X_CXY";
string Fixed = Original.Substring(0, Original.IndexOf("_", 0));
// in case you want to remove all 'X`s' after first occurrence of `'_'`
// just dont use that variable
bool found = false;
for (int i = Original.IndexOf("_", 0); i < Original.Length; i++)
{
if (Original[i].ToString()=="X" && found == false)
{
found = true;
}
else
{
Fixed += Original[i];
}
}
Console.WriteLine(Fixed);
Console.ReadLine();
}

Why not good old IndexOf and Substring?
string s = "AX_1234X_12345_X_CXY";
int pUnder = s.IndexOf('_');
if (pUnder >= 0) { // we have underscope...
int pX = s.IndexOf('X', pUnder + 1); // we should search for X after the underscope
if (pX >= 0) // ...as well as X after the underscope
s = s.Substring(0, pX) + s.Substring(pX + 1);
}
Console.Write(s);
Outcome:
AX_1234_12345_X_CXY

string original = #"AX_1234X_12345_X_CXY";
original = #"AX_1234_12345_X_CXY";

One way is String.Remove, because you can tell exactly where to remove from. If the offending "X" is always in the same place, you can use:
string newString = old.Remove(7,1);
This will remove 1 character starting as position 7 (counting from zero as the beginning of the string).
If not always in the same character position, you might try:
int xPos = old.IndexOf("X");
string newString = old.Remove(xPos,1);
EDIT:
Based on OP comment, the "X" we're targeting occurs just after the first underscore character, so let's index off of the first underscore:
int iPosUnderscore = old.IndexOf("_");
string newString = old.Remove(iPosUnderscore + 1 ,1); // start after the underscore

Try looking at string.IndexOf or string.IndexOfAny
string s = "AX_1234X_12345_X_CXY";
string ns = HappyChap(s);
public string HappyChap(string value)
{
int start = value.IndexOf("X_");
int next = start;
next = value.IndexOf("X_", start + 1);
if (next > 0)
{
value = value.Remove(next, 1);
}
return value;
}

If and only if this is always the format then it should be a simple matter of combining substrings of the original text without including the x in that position. But the op hasn't stated that this is always the case. So if this is always the format and the same character position is always removed then you could simply just
string s = "AX_1234X_12345_X_CXY";
string newstring = s.Substring(0, 7) + s.Substring(8);
OK, based on only the second set of numbers being variable in length, you could then do something like:
int startpos = s.IndexOf('_', 4);
string newstring = s.Substring(0, startpos - 1) + s.Substring(startpos);
with this code, the following tests resulted in:
"AX_1234X_12345_X_CXY" became "AX_1234_12345_X_CXY"
"AX_123X_12345_X_CXY" became "AX_123_12345_X_CXY"
"AX_234X_12345_X_CXY" became "AX_234_12345_X_CXY"
"AX_1X_12345_X_CXY" became "AX_1_12345_X_CXY"

Something like this could work. I'm sure there's a more elegant solution.
string input1 = "AX_1234X_12345_X_CXY";
string pattern1 = "^[A-Z]{1,2}_[0-9]{1,4}(X)";
string newInput = string.Empty;
Match match = Regex.Match(input1, pattern1);
if(match.Success){
newInput = input1.Remove(match.Groups[1].Index, 1);
}
Console.WriteLine(newInput);

Filter text between two special characters

For example I have those strings:
"qwe/qwe/qwe/qwe//qwe/somethinghere_blabla.exe"
"qwe/qwe/q//we/qwe//qwe/somethingother_here_blabla.exe"
"qwe/qwe/qwe/qwe//qwe/some_numbers_here_blabla.exe"
Now I want to get the text between the last '/' and the last '_'.
So the outcome would be:
"somethinghere"
"somethingother_here"
"some_numbers_here"
What is the easiest and clearest way to do this?
I have no idea how to do this, should I split them in '/' and '_', so do this apart? I couldn't think of any way how to do it.
Maybe scan the string from the end till it reaches its first '/' and '_'? Or is there an easier and faster way? Because it has to scan ~10.000 strings.
string[] words = line.Split('/', '_'); //maybe use this? probably not
Thanks in advance!

string s = "qwe/qwe/q//we/qwe//qwe/somethingother_here_blabla.exe";
int last_ = s.LastIndexOf('_');
if (last_ < 0) // _ not found, take the tail of string
last_ = s.Length;
int lastSlash = s.LastIndexOf('/');
string part = s.Substring(lastSlash + 1, last_ - lastSlash - 1);

Well, there is string.LastIndexOf:
var start = line.LastIndexOf('/') + 1;
var end = line.LastIndexOf('_');
var result = line.Substring(start, end - start);

The LINQ way:
var str = "qwe/qwe/qwe/qwe//qwe/somethinghere_blabla.exe";
var newStr = new string(str.Reverse().SkipWhile(c => c != '_').Skip(1).TakeWhile(c => c != '/').Reverse().ToArray());

var string = "qwe/qwe/qwe/qwe//qwe/some_numbers_here_blabla.exe";
var start = string.lastIndexOf("/");
var end = string.lastIndexOf("_");
var result = string.substring(start + 1, end);
Note: above code does not handle error if string does not have / or _ after a last slash

Get string between Two dots c#

how can i get string between two dots for example ?
[Person.Position.Name]
for this case I want to get the string "Position"
I can also have three dots ….
[Person.Location.City.Name]
I want to take all strings between dots

I know it's a year old question, but the other answers are not sufficient, like they are even pretending that you want "Location.City" because they don't know how to seperate them.. The solution is simple though, don't use indexof.
say you want to seperate the Four (not 3) parts:
String input = "Person.Location.City.Name"
string person = input.Split('.')[0];
string location = input.Split('.')[1];
string city = input.Split('.')[2];
string name = input.Split('.')[3];
Console.WriteLine("Person: " + person + "\nLocation: " + location + "\nCity: " + city + "\nName: " + name);

This might help you:
string s = "Person.Position.Name";
int start = s.IndexOf(".") + 1;
int end = s.LastIndexOf(".");
string result = s.Substring(start, end - start);
It will return all the values between the first and the last dot.
If you don't want the result with dot between the strings, you can try this:
string s = "Person.Location.Name";
int start = s.IndexOf(".") + 1;
int end = s.LastIndexOf(".");
var result = s.Substring(start, end - start).Split('.');
foreach (var item in result)
{
//item is some string between the first and the last dot.
//in this case "Location"
}

Try this
string str = "[Person.Location.City.Name]";
int dotFirstIndex = str.IndexOf('.');
int dotLastIndex = str.LastIndexOf('.');
string result = str.Substring((dotFirstIndex + 1), (dotLastIndex - dotFirstIndex) - 1); // output Location.City

strip out digits or letters at the most right of a string

I have a file name: kjrjh20111103-BATCH2242_20111113-091337.txt
I only need 091337, not the txt or the - how can I achieve that. It does not have to be 6 numbers it could be more or less but will always be after "-" and the last ones before ."doc" or ."txt"

You can either do this with a regex, or with simple string operations. For the latter:
int lastDash = text.LastIndexOf('-');
string afterDash = text.Substring(lastDash + 1);
int dot = afterDash.IndexOf('.');
string data = dot == -1 ? afterDash : afterDash.Substring(0, dot);
Personally I find this easier to understand and verify than a regular expression, but your mileage may vary.

String fileName = kjrjh20111103-BATCH2242_20111113-091337.txt;
String[] splitString = fileName.Split ( new char[] { '-', '.' } );
String Number = splitString[2];

Regex: .*-(?<num>[0-9]*). should do the job. num capture group contains your string.

The Regex would be:
string fileName = "kjrjh20111103-BATCH2242_20111113-091337.txt";
string fileMatch = Regex.Match(fileName, "(?<=-)\d+", RegexOptions.IgnoreCase).Value;

String fileName = "kjrjh20111103-BATCH2242_20111113-091337.txt";
var startIndex = fileName.LastIndexOf('-') + 1;
var length = fileName.LastIndexOf('.') - startIndex;
var output = fileName.Substring(startIndex, length);

C# split string on X number of alpha numeric values

this might be simple question I have 3 strings
A123949DADWE2ASDASDW
ASDRWE234DS2334234234
ZXC234ASD43D33SDF23SDF
I want to split those by the first 8 characters and then the 10th and 11th and then combine them into one string.
So I would get:
A123949DWE
ASDRWE23S2
ZXC234AS3D
Basically the 9th character and anything after the 12th character is removed.

You can use String.Substring:
s = s.Substring(0, 8) + s[10] + s[11]
Example code:
string[] a = {
"A123949DADWE2ASDASDW",
"ASDRWE234DS2334234234",
"ZXC234ASD43D33SDF23SDF"
};
a = a.Select(s => s.Substring(0, 8) + s[10] + s[11]).ToArray();
Result:
A123949DWE
ASDRWE23S2
ZXC234AS3D

So let's say you have them declared as string variables:
string s1 = "A123949DADWE2ASDASDW";
string s2 = "ASDRWE234DS2334234234";
string s3 = "ZXC234ASD43D33SDF23SDF";
You can use the substring to get what you want:
string s1substring = s1.Substring(0,8) + s1.Substring(9,2);
string s2substring = s1.Substring(0,8) + s1.Substring(9,2);
string s3substring = s1.Substring(0,8) + s1.Substring(9,2);
And that should give you what you need. Just remember, that the string position is zero-based so you'll have to subtract one from the starting position.

So you could do:
string final1 = GetMyString("A123949DADWE2ASDASDW");
string final2 = GetMyString("ASDRWE234DS2334234234");
string final3 = GetMyString("ZXC234ASD43D33SDF23SDF");
public function GetMyString(string Original)
{
string result = Original.Substring(12);
result = result.Remove(9, 1);
return result;
}