---
title: "Filtered Strings in Data Workflow"
slug: "filtered-strings-in-data-workflow"
tags: ["troubleshooting"]
status: "update"
updated: 2026-10-13T18:21:12Z
published: 2026-10-13T18:21:12Z
canonical: "docs.unqork.io/filtered-strings-in-data-workflow"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://docs.unqork.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Filtered Strings in Data Workflow

The [Filter operator](/unqorkai/docs/data-workflow-operator-reference#filter) in the [Data Workflow component](/unqorkai/docs/data-workflow-component) lets you filter data based on matching values. When a field contains only numbers, the Filter operator might evaluate the value as a number instead of text. When this occurs, the filter finds no match even when the value is present in the data. This is most common with values like IDs, postal codes, or account numbers, which look numeric but must be treated as text for the filter to match correctly.

> [!TIP]
> Describe the filtering issue to the [Build Agent](/unqorkai/docs/build-agent-reference). The agent can identify whether the problem is a type mismatch and suggest the appropriate formula for the configuration.

Two approaches resolve this. Use the artificial letter approach when the filter value is always a string. Use the formula approach when the value entering the argument port might be a number or a string depending on the pipeline context.

## Adding an Artificial Letter to the Argument

Adding a letter to the beginning of the number string forces the Filter operator to read it as text. For example, instead of filtering on `12345`, filter on `T12345`. Add a [Formula operator](/unqorkai/docs/data-workflow-operator-reference#formula) before the Filter and use `CONCATENATE` to add the prefix.

Configure the Formula operator with the following settings:

| Setting | Value |
| --- | --- |
| Category | Formula |
| Label | Concat Filter |
| Formula/Expression | `=CONCATENATE('T',A)` |

`A` represents the value entering the Formula operator's input port — the number string to prefix.

## Converting a Number to a String Using a Formula

If the argument might be a number or a string depending on context, use `IF`, `ISNUMBER`, and `STRINGIFY` to handle both cases. Add a [Formula operator](/unqorkai/docs/data-workflow-operator-reference#formula) before the Filter and configure it with this formula. The formula checks whether the argument is a number; if so, it converts the value to a string before filtering. If the argument is already a string, the filter runs as-is.

Configure the Formula operator with the following settings:

| Setting | Value |
| --- | --- |
| Category | Formula |
| Label | Convert String |
| Formula/Expression | `=IF(ISNUMBER(_arg),STRINGIFY(_arg),_arg)` |

---

**Changelog**

| Date | Change |
| --- | --- |
| 2026-10-09 | Added inline links; inline code for formula functions in prose; expanded intro with type mismatch symptom and when-to-use guidance; clarified A variable description. |
| 2026-07-16 | Initial publication. |

A string is an object that represents a sequence of characters. Strings typically hold data represented in text form.

Label Text conveys what the input component is and what information it displays. Enter the purpose of the corresponding component or field.