c# Put spaces between words starting with capital letters

To place spaces between words starting with capital letters in C#, you can use LINQ to examine each character and insert spaces before uppercase letters. This technique is commonly used to format PascalCase strings into readable text.

Syntax

The basic syntax using LINQ to add spaces before capital letters −

string.Concat(str.Select(x => Char.IsUpper(x) ? " " + x : x.ToString())).TrimStart(' ');

Using LINQ with Select and IsUpper

The following example demonstrates how to add spaces before each uppercase letter in a PascalCase string −

using System;
using System.Linq;

class Demo {
    static void Main() {
        var str = "WelcomeToMyWebsite";
        
        Console.WriteLine("Original String: " + str);
        str = string.Concat(str.Select(x => Char.IsUpper(x) ? " " + x : x.ToString())).TrimStart(' ');
        
        Console.WriteLine("New String: " + str);
    }
}

The output of the above code is −

Original String: WelcomeToMyWebsite
New String: Welcome To My Website

Using Regular Expressions

An alternative approach uses regular expressions to insert spaces before uppercase letters −

using System;
using System.Text.RegularExpressions;

class Demo {
    static void Main() {
        string str = "HelloWorldFromCSharp";
        
        Console.WriteLine("Original String: " + str);
        string result = Regex.Replace(str, "([A-Z])", " $1").Trim();
        
        Console.WriteLine("New String: " + result);
    }
}

The output of the above code is −

Original String: HelloWorldFromCSharp
New String: Hello World From C Sharp

Using StringBuilder for Better Performance

For larger strings, StringBuilder provides better performance −

using System;
using System.Text;

class Demo {
    static void Main() {
        string str = "MyVeryLongPascalCaseString";
        StringBuilder sb = new StringBuilder();
        
        for (int i = 0; i < str.Length; i++) {
            if (i > 0 && Char.IsUpper(str[i])) {
                sb.Append(' ');
            }
            sb.Append(str[i]);
        }
        
        Console.WriteLine("Original String: " + str);
        Console.WriteLine("New String: " + sb.ToString());
    }
}

The output of the above code is −

Original String: MyVeryLongPascalCaseString
New String: My Very Long Pascal Case String

Comparison of Methods

Conclusion

Adding spaces between words starting with capital letters in C# can be accomplished using LINQ, regular expressions, or StringBuilder. The LINQ approach is concise for small strings, while StringBuilder offers better performance for larger text processing tasks.