Add string.Replace(...) and string.ReplaceWhiteSpace(...)

PowerKit.Tests/Extensions/StringExtensionsTests.cs

@@ -6,6 +6,26 @@ namespace PowerKit.Tests.Extensions;
 
 public class StringExtensionsTests
 {
+    [Fact]
+    public void Replace_Test()
+    {
+        // Act & assert
+        "a1b2c3".Replace(ch => char.IsDigit(ch) ? '*' : ch).Should().Be("a*b*c*");
+        "hello".Replace(ch => ch).Should().Be("hello");
+        "".Replace(ch => ch).Should().Be("");
+    }
+
+    [Fact]
+    public void ReplaceWhiteSpace_Test()
+    {
+        // Act & assert
+        "hello world".ReplaceWhiteSpace('_').Should().Be("hello_world");
+        "hello\tworld\nfoo".ReplaceWhiteSpace('-').Should().Be("hello-world-foo");
+        "hello\u00A0world".ReplaceWhiteSpace(' ').Should().Be("hello world");
+        "helloworld".ReplaceWhiteSpace('_').Should().Be("helloworld");
+        "".ReplaceWhiteSpace('_').Should().Be("");
+    }
+
     [Fact]
     public void Reverse_Test()
     {

PowerKit/Extensions/StringExtensions.cs

@@ -1,6 +1,7 @@
 #nullable enable
 using System;
 using System.Diagnostics.CodeAnalysis;
+using System.Linq;
 using System.Security;
 using System.Text;
 
@@ -13,6 +14,34 @@ internal static class StringExtensions
 {
     extension(string str)
     {
+        /// <summary>
+        /// Replaces each character using the replacement produced by the provided selector.
+        /// </summary>
+        public string Replace(Func<char, char> getReplacement) =>
+            string.Create(
+                str.Length,
+                (str, getReplacement),
+                static (chars, source) =>
+                {
+                    foreach (var (i, ch) in source.str.Index())
+                    {
+                        chars[i] = source.getReplacement(ch);
+                    }
+                }
+            );
+
+        /// <summary>
+        /// Replaces each whitespace character using the replacement produced by the provided selector.
+        /// </summary>
+        public string ReplaceWhiteSpace(Func<char, char> getReplacement) =>
+            str.Replace(ch => char.IsWhiteSpace(ch) ? getReplacement(ch) : ch);
+
+        /// <summary>
+        /// Replaces each whitespace character with the specified replacement character.
+        /// </summary>
+        public string ReplaceWhiteSpace(char replacement) =>
+            str.ReplaceWhiteSpace(_ => replacement);
+
         /// <summary>
         /// Returns the string with the characters in reverse order.
         /// </summary>