Get string between two strings in a string

Question

I have a string like:

\"super exemple of string key : text I want to keep - end of my string\"

I want to just keep the string which is betw

Answer 1

Depending on how robust/flexible you want your implementation to be, this can actually be a bit tricky. Here's the implementation I use:

public static class StringExtensions {
    /// 

    /// takes a substring between two anchor strings (or the end of the string if that anchor is null)
    /// 
    /// a string
    /// an optional string to search after
    /// an optional string to search before
    /// an optional comparison for the search
    /// a substring based on the search
    public static string Substring(this string @this, string from = null, string until = null, StringComparison comparison = StringComparison.InvariantCulture)
    {
        var fromLength = (from ?? string.Empty).Length;
        var startIndex = !string.IsNullOrEmpty(from) 
            ? @this.IndexOf(from, comparison) + fromLength
            : 0;

        if (startIndex < fromLength) { throw new ArgumentException("from: Failed to find an instance of the first anchor"); }

            var endIndex = !string.IsNullOrEmpty(until) 
            ? @this.IndexOf(until, startIndex, comparison) 
            : @this.Length;

        if (endIndex < 0) { throw new ArgumentException("until: Failed to find an instance of the last anchor"); }

        var subString = @this.Substring(startIndex, endIndex - startIndex);
        return subString;
    }
}

// usage:
var between = "a - to keep x more stuff".Substring(from: "-", until: "x");
// returns " to keep "