uCalc API Version: 2.1.3-preview.2 Released: 6/16/2026

Warning

uCalc API Preview Release Notice:The documentation describes the intended behavior of the API. The current preview build contains incomplete features, unoptimized performance, and is subject to breaking changes.

Between

Method

Product: 

String Library

Class: 

String

Creates a live, modifiable view of the substring located between two specified patterns.

Syntax

Between(string, string, int, int)

Parameters

startPattern
string
The pattern marking the beginning of the text to extract. The view starts immediately after this pattern.
stopPattern
string
The pattern marking the end of the text to extract. The view ends immediately before this pattern.
startNth
int
(Default = 1)
A 1-based index specifying which occurrence of `startPattern` to use as the starting boundary.
stopNth
int
(Default = 1)
A 1-based index specifying which occurrence of `stopPattern` to use as the ending boundary.

Return

String

A new uCalc.String object representing a live, modifiable view into the portion of the parent string between the specified patterns. Returns an empty string object if the patterns are not found.

Remarks

✂️ Extracting Text Between Two Patterns

The Between method finds the text located between two specified patterns and returns it as a new uCalc.String object. This is a fundamental tool for parsing structured data and is a core part of the fluent, chainable API, often used with methods like After and Before.

✨ The "Live View" Concept

The most important feature of this method is that it does not return a simple, disconnected substring. Instead, it returns a live, modifiable view into the parent string. This means:

  • Any modifications made to the child string (the returned view) will directly affect the content of the original parent string.
  • This allows for powerful, in-place editing of specific sections of a larger document without the overhead of creating and rejoining substrings.

⚙️ Parameters

  • startPattern & stopPattern: These define the boundaries of the text to be extracted. The returned view contains only the content between these boundaries, not including the boundaries themselves.
  • startNth & stopNth: These 1-based indices allow you to handle documents with repeated patterns. For example, Between("(", ")", 2) would find the text inside the second set of parentheses.

If either pattern is not found, the method returns an empty uCalc.String object without raising an error.

💡 Why uCalc? (Comparative Analysis)

In a standard language like C#, extracting text between two markers requires a manual, multi-step process involving IndexOf and Substring.

C# Manual Approach:

string text = "Config{value=123}";int startIndex = text.IndexOf("{") + 1;int endIndex = text.IndexOf("}");if (startIndex != 0 && endIndex != -1){    string value = text.Substring(startIndex, endIndex - startIndex);    // 'value' is a new, disconnected string: "value=123"}

This approach is imperative, character-based, and creates disconnected data. uCalc.String provides a more powerful, declarative, and integrated solution:

The uCalc Advantage:

var s = new uCalc.String("Config{value=123}");var valueView = s.Between("{", "}"); // Returns a live, token-aware view// Modifying the view changes the original string 's'valueView.Replace("123", "CHANGED");Console.WriteLine(s); // Output: Config{value=CHANGED}

This ability to create live, token-aware, chainable views is a key differentiator, enabling a more fluid and powerful style of text manipulation that is not possible with standard string libraries.

Examples

A succinct example demonstrating how to extract text contained within a pair of parentheses.
				
					using uCalcSoftware;

var uc = new uCalc();
using (var s = new uCalc.String("Data (important) more data")) {
   
   // Get the text between the opening and closing parenthesis
   var content = s.Between("(", ")");

   Console.WriteLine(content);
}
				
			
important
				
					#include <iostream>
#include "uCalc.h"

using namespace std;
using namespace uCalcSoftware;

int main() {
   uCalc uc;
   {
      uCalc::String s("Data (important) more data");
      s.Owned(); // Causes s to be released when it goes out of scope

      // Get the text between the opening and closing parenthesis
      auto content = s.Between("(", ")");

      cout << content << endl;
   }
}
				
			
important
				
					Imports System
Imports uCalcSoftware
Public Module Program
   Public Sub Main()
      Dim uc As New uCalc()
      Using s As New uCalc.String("Data (important) more data")
         
         '// Get the text between the opening and closing parenthesis
         Dim content = s.Between("(", ")")
         
         Console.WriteLine(content)
      End Using
   End Sub
End Module
				
			
important
A practical example of parsing a value from a simple key-value pair in a configuration string.
				
					using uCalcSoftware;

var uc = new uCalc();
using (var s = new uCalc.String("User: admin; Role: user; Department: Sales;")) {
   
   // Extract the text between 'Department: ' and the trailing semicolon
   var department = s.Between("Department: ", ";");

   Console.WriteLine($"Department is '{department}'");
}
				
			
Department is ' Sales'
				
					#include <iostream>
#include "uCalc.h"

using namespace std;
using namespace uCalcSoftware;

int main() {
   uCalc uc;
   {
      uCalc::String s("User: admin; Role: user; Department: Sales;");
      s.Owned(); // Causes s to be released when it goes out of scope

      // Extract the text between 'Department: ' and the trailing semicolon
      auto department = s.Between("Department: ", ";");

      cout << "Department is '" << department << "'" << endl;
   }
}
				
			
Department is ' Sales'
				
					Imports System
Imports uCalcSoftware
Public Module Program
   Public Sub Main()
      Dim uc As New uCalc()
      Using s As New uCalc.String("User: admin; Role: user; Department: Sales;")
         
         '// Extract the text between 'Department: ' and the trailing semicolon
         Dim department = s.Between("Department: ", ";")
         
         Console.WriteLine($"Department is '{department}'")
      End Using
   End Sub
End Module
				
			
Department is ' Sales'
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