Develop Reference

Is there built-in method to add character multiple times to a string?

Is there a built-in function or more efficient way to add character to a string X number of times?
for example the following code will add '0' character 5 times to the string:
int count = 5;
char someChar = '0';
string myString = "SomeString";
for(int i=0;i<count;i++)
{
myString = someChar + myString;
}

Use PadLeft() or PadRight()
An example for PadRight():
int count = 5;
char someChar = '0';
string myString = "SomeString";
myString = myString.PadRight(count + myString.Length, someChar);
// output -> "SomeString00000"
Remember the first parameter of either method is the total string length required hence why I am adding count to the original string length.
Likewise if you want to append the character at the start of the string use PadLeft()
myString = myString.PadLeft(count + myString.Length, someChar);
// output -> "00000SomeString"

string.Concat(Enumerable.Repeat("0", 5));
will return
"00000"
Refered from :Is there a built-in function to repeat string or char in .net?

You can also do it as:
string line = "abc";
line = "abc" + new String('X', 5);
//line == abcXXXXX

Take a look here, You can use PadRight() / PadLeft();
int count = 5;
char someChar = '0';
string myString = "SomeString";
var stringLength = myString.Length;
var newPaddedStringRight = myString.PadRight(stringLength + count, '0');
//will give SomeString00000
var newPaddedStringLeft = myString.PadLeft(stringLength + count, '0');
//will give 00000SomeString
Remember, a string is Immutable, so you'll need to assign the result to a new string.

You could also use StringBuilder. As the string size increases the += incurs a cost on array copy.

Trim a string in c# after special character

I want to trim a string after a special character..
Lets say the string is str="arjunmenon.uking". I want to get the characters after the . and ignore the rest. I.e the resultant string must be restr="uking".

How about:
string foo = str.EverythingAfter('.');
using:
public static string EverythingAfter(this string value, char c)
{
if(string.IsNullOrEmpty(value)) return value;
int idx = value.IndexOf(c);
return idx < 0 ? "" : value.Substring(idx + 1);
}

you can use like
string input = "arjunmenon.uking";
int index = input.LastIndexOf(".");
input = input.Substring(index+1, input.Split('.')[1].ToString().Length );

Use Split function
Try this
string[] restr = str.Split('.');
//restr[0] contains arjunmenon
//restr[1] contains uking

char special = '.';
var restr = str.Substring(str.IndexOf(special) + 1).Trim();

Try Regular Expression Language
using System.IO;
using System;
using System.Text.RegularExpressions;
class Program
{
static void Main()
{
string input = "arjunmenon.uking";
string pattern = #"[a-zA-Z0-9].*\.([a-zA-Z0-9].*)";
foreach (Match match in Regex.Matches(input, pattern))
{
Console.WriteLine(match.Value);
if (match.Groups.Count > 1)
for (int ctr = 1; ctr < match.Groups.Count; ctr++)
Console.WriteLine(" Group {0}: {1}", ctr, match.Groups[ctr].Value);
}
}
}
Result:
arjunmenon.uking
Group 1: uking

Personally, I won't do the split and go for the index[1] in the resulting array, if you already know that your correct stuff is in index[1] in the splitted string, then why don't you just declare a constant with the value you wanted to "extract"?
After you make a Split, just get the last item in the array.
string separator = ".";
string text = "my.string.is.evil";
string[] parts = text.Split(separator);
string restr = parts[parts.length - 1];
The variable restr will be = "evil"

string str = "arjunmenon.uking";
string[] splitStr = str.Split('.');
string restr = splitStr[1];

Not like the methods that uses indexes, this one will allow you not to use the empty string verifications, and the presence of your special caracter, and will not raise exceptions when having empty strings or string that doesn't contain the special caracter:
string str = "arjunmenon.uking";
string restr = str.Split('.').Last();
You may find all the info you need here : http://msdn.microsoft.com/fr-fr/library/b873y76a(v=vs.110).aspx
cheers

I think the simplest way will be this:
string restr, str = "arjunmenon.uking";
restr = str.Substring(str.LastIndexOf('.') + 1);

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;
}

How to make a first letter capital in C#

How can the first letter in a text be set to capital?
Example:
it is a text. = It is a text.

public static string ToUpperFirstLetter(this string source)
{
if (string.IsNullOrEmpty(source))
return string.Empty;
// convert to char array of the string
char[] letters = source.ToCharArray();
// upper case the first char
letters[0] = char.ToUpper(letters[0]);
// return the array made of the new char array
return new string(letters);
}

It'll be something like this:
// precondition: before must not be an empty string
String after = before.Substring(0, 1).ToUpper() + before.Substring(1);

polygenelubricants' answer is fine for most cases, but you potentially need to think about cultural issues. Do you want this capitalized in a culture-invariant way, in the current culture, or a specific culture? It can make a big difference in Turkey, for example. So you may want to consider:
CultureInfo culture = ...;
text = char.ToUpper(text[0], culture) + text.Substring(1);
or if you prefer methods on String:
CultureInfo culture = ...;
text = text.Substring(0, 1).ToUpper(culture) + text.Substring(1);
where culture might be CultureInfo.InvariantCulture, or the current culture etc.
For more on this problem, see the Turkey Test.

If you are using C# then try this code:
Microsoft.VisualBasic.StrConv(sourceString, Microsoft.VisualBasic.vbProperCase)

I use this variant:
private string FirstLetterCapital(string str)
{
return Char.ToUpper(str[0]) + str.Remove(0, 1);
}

If you are sure that str variable is valid (never an empty-string or null), try:
str = Char.ToUpper(str[0]) + str[1..];
Unlike the other solutions that use Substring, this one does not do additional string allocations. This example basically concatenates char with ReadOnlySpan<char>.

I realize this is an old post, but I recently had this problem and solved it with the following method.
private string capSentences(string str)
{
string s = "";
if (str[str.Length - 1] == '.')
str = str.Remove(str.Length - 1, 1);
char[] delim = { '.' };
string[] tokens = str.Split(delim);
for (int i = 0; i < tokens.Length; i++)
{
tokens[i] = tokens[i].Trim();
tokens[i] = char.ToUpper(tokens[i][0]) + tokens[i].Substring(1);
s += tokens[i] + ". ";
}
return s;
}
In the sample below clicking on the button executes this simple code outBox.Text = capSentences(inBox.Text.Trim()); which pulls the text from the upper box and puts it in the lower box after the above method runs on it.

Take the first letter out of the word and then extract it to the other string.
strFirstLetter = strWord.Substring(0, 1).ToUpper();
strFullWord = strFirstLetter + strWord.Substring(1);

text = new String(
new [] { char.ToUpper(text.First()) }
.Concat(text.Skip(1))
.ToArray()
);

this functions makes capital the first letter of all words in a string
public static string FormatSentence(string source)
{
var words = source.Split(' ').Select(t => t.ToCharArray()).ToList();
words.ForEach(t =>
{
for (int i = 0; i < t.Length; i++)
{
t[i] = i.Equals(0) ? char.ToUpper(t[i]) : char.ToLower(t[i]);
}
});
return string.Join(" ", words.Select(t => new string(t)));;
}

string str = "it is a text";
// first use the .Trim() method to get rid of all the unnecessary space at the begining and the end for exemple (" This string ".Trim() is gonna output "This string").
str = str.Trim();
char theFirstLetter = str[0]; // this line is to take the first letter of the string at index 0.
theFirstLetter.ToUpper(); // .ToTupper() methode to uppercase the firstletter.
str = theFirstLetter + str.substring(1); // we add the first letter that we uppercased and add the rest of the string by using the str.substring(1) (str.substring(1) to skip the first letter at index 0 and only print the letters from the index 1 to the last index.)
Console.WriteLine(str); // now it should output "It is a text"

static String UppercaseWords(String BadName)
{
String FullName = "";
if (BadName != null)
{
String[] FullBadName = BadName.Split(' ');
foreach (string Name in FullBadName)
{
String SmallName = "";
if (Name.Length > 1)
{
SmallName = char.ToUpper(Name[0]) + Name.Substring(1).ToLower();
}
else
{
SmallName = Name.ToUpper();
}
FullName = FullName + " " + SmallName;
}
}
FullName = FullName.Trim();
FullName = FullName.TrimEnd();
FullName = FullName.TrimStart();
return FullName;
}

string Input = " it is my text";
Input = Input.TrimStart();
//Create a char array
char[] Letters = Input.ToCharArray();
//Make first letter a capital one
string First = char.ToUpper(Letters[0]).ToString();
//Concatenate
string Output = string.Concat(First,Input.Substring(1));

Try this code snippet:
char nm[] = "this is a test";
if(char.IsLower(nm[0])) nm[0] = char.ToUpper(nm[0]);
//print result: This is a test

Convert int to string?

How can I convert an int datatype into a string datatype in C#?

string myString = myInt.ToString();

string a = i.ToString();
string b = Convert.ToString(i);
string c = string.Format("{0}", i);
string d = $"{i}";
string e = "" + i;
string f = string.Empty + i;
string g = new StringBuilder().Append(i).ToString();

Just in case you want the binary representation and you're still drunk from last night's party:
private static string ByteToString(int value)
{
StringBuilder builder = new StringBuilder(sizeof(byte) * 8);
BitArray[] bitArrays = BitConverter.GetBytes(value).Reverse().Select(b => new BitArray(new []{b})).ToArray();
foreach (bool bit in bitArrays.SelectMany(bitArray => bitArray.Cast<bool>().Reverse()))
{
builder.Append(bit ? '1' : '0');
}
return builder.ToString();
}
Note: Something about not handling endianness very nicely...
If you don't mind sacrificing a bit of memory for speed, you can use below to generate an array with pre-calculated string values:
static void OutputIntegerStringRepresentations()
{
Console.WriteLine("private static string[] integerAsDecimal = new [] {");
for (int i = int.MinValue; i < int.MaxValue; i++)
{
Console.WriteLine("\t\"{0}\",", i);
}
Console.WriteLine("\t\"{0}\"", int.MaxValue);
Console.WriteLine("}");
}

int num = 10;
string str = Convert.ToString(num);

The ToString method of any object is supposed to return a string representation of that object.
int var1 = 2;
string var2 = var1.ToString();

Further on to #Xavier's response, here's a page that does speed comparisons between several different ways to do the conversion from 100 iterations up to 21,474,836 iterations.
It seems pretty much a tie between:
int someInt = 0;
someInt.ToString(); //this was fastest half the time
//and
Convert.ToString(someInt); //this was the fastest the other half the time

string str = intVar.ToString();
In some conditions, you do not have to use ToString()
string str = "hi " + intVar;

or:
string s = Convert.ToString(num);

using System.ComponentModel;
TypeConverter converter = TypeDescriptor.GetConverter(typeof(int));
string s = (string)converter.ConvertTo(i, typeof(string));

None of the answers mentioned that the ToString() method can be applied to integer expressions
Debug.Assert((1000*1000).ToString()=="1000000");
even to integer literals
Debug.Assert(256.ToString("X")=="100");
Although integer literals like this are often considered to be bad coding style (magic numbers) there may be cases where this feature is useful...

string s = "" + 2;
and you can do nice things like:
string s = 2 + 2 + "you"
The result will be:
"4 you"

if you're getting from a dataset
string newbranchcode = (Convert.ToInt32(ds.Tables[0].Rows[0]["MAX(BRANCH_CODE)"]) ).ToString();