# Set list field value transform action

## Use case

You have a list of objects where certain field values need adjusting. You need a solution that not only allows straightforward field value modifications, but also supports conditional changes and nested element modifications.

## Overview

<figure><img src="https://1835401289-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FAQQ1EHVcEsGKBPVHmiav%2Fuploads%2FwFjykJj3VCdJbd4ysTyf%2FScreenshot%202025-03-28%20at%2011.27.48%E2%80%AFAM.png?alt=media&#x26;token=dfa7c221-c556-457c-b153-133b75b5a7ab" alt=""><figcaption></figcaption></figure>

The `Set List Field Value` action enables the customization of a field's value within a list of objects. Whether it's for conditional value adjustment based on specific criteria or working with nested elements, this action offers the flexibility you need.

<figure><img src="https://1835401289-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FAQQ1EHVcEsGKBPVHmiav%2Fuploads%2FbjS5FjzOVRhvfY0TB0GA%2FScreenshot%202025-03-24%20at%2010.57.50%E2%80%AFAM.png?alt=media&#x26;token=9744d27b-e1de-4383-934a-102d6a4d1896" alt=""><figcaption></figcaption></figure>

## Parameters

<table><thead><tr><th width="178">Parameter</th><th width="472.3333333333333">Description</th><th data-type="checkbox">Required</th><th data-hidden>Required</th></tr></thead><tbody><tr><td>List to Transform</td><td>The list of objects you want to modify the contents of.</td><td>true</td><td>Yes</td></tr><tr><td>Field to Update</td><td>Specify the field to be added or modified in each object.</td><td>true</td><td>Yes</td></tr><tr><td>New Value</td><td>Specify the value for the new or modified field.</td><td>true</td><td>Yes</td></tr><tr><td>New Value Mode</td><td>How you want to provide the field's new value. <code>copy_from_field</code> or <code>set_value</code> (described below)</td><td>true</td><td>Yes</td></tr><tr><td>Parent Fields</td><td>If the field should be nested within another list, specify the parent list's name here.</td><td>false</td><td>No</td></tr><tr><td>Condition Field</td><td>If you want to update the field conditionally, specify the field to base the condition on.</td><td>false</td><td>No</td></tr><tr><td>Condition Value</td><td>If a <code>Condition Field</code> is specified, provide the value that should be matched to trigger the update.</td><td>false</td><td>No</td></tr></tbody></table>

## Usage

Let's break this down into specific use-case examples, to show how each of these methods can be used within the `Set Field Value` Transform.

### Input list

Assume that we have a list of objects called `my_list` that looks like this:

```json
my_list: [
  {
    name: "John",
    age: 30,
    hobbies: ["golf", "reading"],
  },
  {
    name: "Mary",
    age: 35,
    hobbies: ["cooking", "music"],
  },
]
```

### Update methods

Using the `New Value Mode` you can define how you want to provide the data for the outputting field. You can do one of two things:

* **Copy From Field:** allows you to copy the value from an existing field
* **Set Value:** provide the literal value you'd like the field to be set to.

Here are some examples of how we can use this action to update or add to our list:

<details>

<summary>Example 1: Create and set new field values</summary>

Add a new field `adult` with value `true` to each object in the list.

**Action Parameters:**

```yaml
field_actions:
 field: adult
 new_value: true
 new_value_mode: set_value
```

**Jinja2 Equivalent:**

```django
{% set _ = item.update({'adult': true}) %}


```

</details>

<details>

<summary>Example 2: Copy value from existing field to new field</summary>

Copy the `age` field to a new field `years` in each object.

**Action Parameters:**

```yaml
field_actions:
 field: years
 new_value: age
 new_value_mode: copy_from_field
```

**Jinja2 Equivalent:**

```django
{% set _ = item.update({'years': item['age']}) %}


```

</details>

<details>

<summary>Example 3: Update fields conditionally based on other fields</summary>

Update the `name` field to `Senior` for any object where `age` is 35.

**Action Parameters:**

```yaml
field_actions:
 field: name
 new_value: "Senior"
 new_value_mode: set_value
 condition_field: age
 condition_value: 35
```

**Jinja2 Equivalent:**

```django
{% if item['age'] == 35 %}
  {% set _ = item.update({'name': 'Senior'}) %}
{% endif %}
```

</details>

### Results output

After all these examples are performed in the transformation, your newly updated list would reflect these changes in their outputted results as such:

```json
results: [
  {
    name: "John",
    age: 30,
    hobbies: ["golf", "reading"],
    adult: true,
    years: 30
  },
  {
    name: "Senior",
    age: 35,
    hobbies: ["cooking", "music"],
    adult: true,
    years: 35
  },
]
```