---
title: Concatenate array
description: Merge multiple array columns into a single concatenated array column.
category: Data Transformation
tags: [array, merge, combine, transformation, concatenate]
---

# Concatenate array

## Description

The **Concatenate Array** activity merges arrays from multiple columns into a single array column. It supports retaining original columns or producing only the result column based on configuration.

Use this activity to:

- Combine related list-type fields from multiple columns.
- Simplify downstream processing by unifying scattered array data.
- Retain or replace source columns based on your output needs.

> **Use case**: You have two columns with product tags or keyword lists and want to combine them into a unified `All Tags` column for export or further analysis.

## Input

| Input Type | Format   | Description                                 |
| ---------- | -------- | ------------------------------------------- |
| **Data**   | Required | Tabular data containing array-type columns. |

## Output

| Output Type | Format | Description                                 |
| ----------- | ------ | ------------------------------------------- |
| **Data**    | JSON   | Transformed data with combined array column |

## Configuration Fields

| Field Name           | Description                                                                                         |
| -------------------- | --------------------------------------------------------------------------------------------------- |
| **Column Names**     | List of columns containing arrays to be concatenated.                                               |
| **Output Column**    | Name of the new column to store the resulting array.                                                |
| **Include Original** | If enabled, includes all input columns in the output. If disabled, only the output column is shown. |

## Sample Input

| ID  | Column A        | Column B   |
| --- | --------------- | ---------- |
| 1   | ["apple"]       | ["banana"] |
| 2   | ["cat"]         | ["dog"]    |
| 3   | ["red", "blue"] | ["green"]  |

## Sample Configuration

| Field              | Value                      |
| ------------------ | -------------------------- |
| `Column Names`     | `["Column A", "Column B"]` |
| `Output Column`    | `Concatenated Array`       |
| `Include Original` | `true`                     |

## Sample Output 1 (Include Original = true)

| ID  | Column A        | Column B   | Concatenated Array       |
| --- | --------------- | ---------- | ------------------------ |
| 1   | ["apple"]       | ["banana"] | ["apple", "banana"]      |
| 2   | ["cat"]         | ["dog"]    | ["cat", "dog"]           |
| 3   | ["red", "blue"] | ["green"]  | ["red", "blue", "green"] |

## Sample Output 2 (Include Original = false)

| Concatenated Array       |
| ------------------------ |
| ["apple", "banana"]      |
| ["cat", "dog"]           |
| ["red", "blue", "green"] |