String Operations
Defining and Initialising strings
string string1;
string string2 = null;
string string3 = String.Empty;
string string4 = "C:\\Development\\Projects";
string string5 = @"C:\Development\Projects";
String string6 = "Latest string";
var string7 = "Implicit string";
const string string8 = "This text cannot be changed at runtime.";
char[] charArray = new char[] { 'H', 'e', 'l', 'l', 'o' };
string string9 = new string(charArray);
Char from String
You can access each character of the string with an indexer
char charFromString = fooString[1]; // => 'e'
// Strings are immutable: you can't do fooString[1] = 'X';
String to Char-Array
string text = "Hallo";
char[] charArray = text.ToCharArray();
// Ausgabe jedes Zeichens
foreach (char c in charArray)
{
Console.WriteLine(c);
}
String to Char-Array mit LINQ
string text = "Hallo";
char[] charArray = text.Select(c => c).ToArray(); // Alternativ mit LINQ
Console.WriteLine(new string(charArray)); // Ausgabe: Hallo
StringBuilder AppendLine
StringBuilder sb = new StringBuilder();
sb.Append("Hello ");
sb.AppendLine("World!");
Console.WriteLine(sb);
// Ausgabe: Hello World!
Verbatim String
You can use the @ symbol before a string literal to escape all characters in the string
string path = "C:\\Users\\User\\Desktop";
string verbatimPath = @"C:\Users\User\Desktop";
Console.WriteLine(path == verbatimPath); // => true
// You can split a string over two lines with the @ symbol. To escape " use ""
string bazString = @"Here's some stuff
on a new line! ""Wow!"", the masses cried";
String IndexOf
string myText = "some text";
Console.WriteLine(myText.IndexOf('t')); // Outputs => 5
String Insert
string myText = "some text";
myText = myText.Insert(0, "This is ");
Console.WriteLine(myText);
// Outputs => "This is some text"
String Replace
string myText = "This is some text"
myText = myText.Replace("This is", "Here is");
Console.WriteLine(myText);
// Outputs => "Here is some text"
String Contains
string myText = "This is some text"
if(myText.Contains("some"))
Console.WriteLine("found");
// Outputs "found"
String Remove
string myText = "This is some text"
myText = myText.Remove(4);
Console.WriteLine(myText);
// Outputs "This"
String Substring
string myText = "This is some text"
myText = myText.Substring(2, 3);
Console.WriteLine(myText);
// Outputs "is"
String Slicing
- Index: Mit
^kannst Du vom Ende her indexieren (z. B.^1für das letzte Element). - Range: Mit
..definierst Du einen Bereich. Dabei ist das Ende exklusiv.
string text = "Hallo Welt";
// Teilausschnitt ab Index 6 bis zum Ende
string teilText1 = text[6..]; // "Welt"
// Teilausschnitt von Index 0 bis 5
string teilText2 = text[..5]; // "Hallo"
Quick-Reference: String Methoden
| Method | Code | Comments |
|---|---|---|
| Clone() | firstName.Clone() | Make clone of string |
| CompareTo() | firstName.CompareTo(lastname) | Compare two strings and returns integer value as output. It returns 0 for true and 1 for false |
| Contains | firstName.Contains("Dav") | The Contains method checks whether specified character or string is exists or not in the string value |
| EndsWith() | firstName.EndsWith("n") | This EndsWith Method checks whether specified character is the last character of string or not |
| Equals() | firstnName.Equals(lastname) | The Equals Method in C# compares two string and returns Boolean value as output |
| GetHashCode() | firstName.GetHashCode() | This method returns HashValue of specified string |
| GetType() | firstName.GetType() | Returns the System.Type of current instance |
| IndexOf() | firstName.IndexOf("e") | Returns the index position of first occurrence of specified character |
| ToLower() | firstName.ToLower() | Converts String into lower case based on rules of the current culture |
| ToUpper() | firstName.ToUper() | Converts String into upper case based on rules of the current culture |
| Insert() | firstName.Insert(0, "Hello") | Insert the string or character in the string at the specified position |
| IsNormalized() | firstName.IsNormalized() | This method checks whether this string is in Unicode normalization form C |
| LastIndexOf() | firsName.LastIndexOf("e") | This method checks whether this string is in Unicode normalization form C |
| Length | firstName.Length | It is a string property that returns length of string |
| Remove() | firstName.Remove(5) | This method deletes all the characters from beginning to specified index position |
| Replace() | firstName.Replace('e','i') | This method replaces the character |
| Split() | string[] split = firstname.Split(new char[] e); | This method splits the string based on specified value |
| StartsWith() | firstName.StartsWith("S") | It checks whether the first character of string is same as specified character |
| Substring() | firstName.Substring(2,5) | This method returns substring |
| ToCharArray() | firstnName.ToCharArray() | Converts string into char array |
| Trim() | firstnName.Trim() | It removes extra whitespaces from beginning and ending of string |