> For the complete documentation index, see [llms.txt](https://docs.augelab.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.augelab.com/function-blocks/blocks-reference/data-logic/data-operations/find-substring.md).

# Find Substring

This function block searches a shorter text inside a longer text and returns a boolean result indicating whether the shorter text exists in the longer one. It is ideal for simple text checks, triggers and conditional logic in your scenarios.

## 📥 Inputs <a href="#inputs" id="inputs"></a>

`Main Text` The text to be searched.

`Sub Text` The substring to look for inside the main text.

## 📤 Outputs <a href="#outputs" id="outputs"></a>

`Result` Boolean value: TRUE when the substring is found in the main text, otherwise FALSE.

## 🕹️ Controls <a href="#controls" id="controls"></a>

`No Controls` This block has no interactive widgets. It operates only using its input sockets.

## 🎯 Features <a href="#features" id="features"></a>

* Fast boolean check to verify presence of a substring in a text.
* Safe behavior when inputs are empty: returns FALSE if required text is missing.
* Minimal configuration — just provide the texts and read the boolean output.

## 📝 Usage Instructions <a href="#usage" id="usage"></a>

1. Provide the longer text into the `Main Text` input socket. You can use a `String Input` block or any other block that outputs text.
2. Provide the substring to search into the `Sub Text` input socket.
3. Read the boolean value from the `Result` output socket to decide downstream actions (for example, trigger logging or alerts).

## 📊 Evaluation <a href="#evaluation" id="evaluation"></a>

When evaluated, this block checks whether the `Sub Text` exists within the `Main Text` and outputs the check result via the `Result` socket.

## 💡 Tips and Tricks <a href="#tips-and-tricks" id="tips-and-tricks"></a>

* To avoid case-sensitivity issues, combine with `String Operations` to convert both texts to a common case before checking.
* Use `String Merge` to build dynamic messages (for example combine variable parts into a single `Main Text`).
* Use `Is None` or `Replace None` before this block to ensure empty inputs are handled predictably.
* Feed the boolean `Result` into a `Logic Input` or other logic blocks (like `And`, `Or`) to drive conditional flows.
* Use `Debug Input` or `Data to JSON` to log matches during development and troubleshooting.
* To store or export match events, combine the boolean output with `CSV Export` or `Image Logger` workflows depending on your data needs.

## 🛠️ Troubleshooting <a href="#troubleshooting" id="troubleshooting"></a>

* No matches but expected: check for case differences or leading/trailing spaces. Normalize text with `String Operations` (e.g., lowercasing, trimming) before feeding this block.
* Always FALSE: ensure both `Main Text` and `Sub Text` sockets are receiving valid text. Use `Debug Input` to inspect upstream values.
* Unexpected TRUE matches: verify the exact substring provided; small typos or partial words may still produce a match depending on the content.