opensearch-docs-cn/_data-prepper/pipelines/configuration/processors/lowercase-string.md

---
layout: default
title: lowercase_string
parent: Processors
grand_parent: Pipelines
nav_order: 45
---

# lowercase_string

## Overview

Converts a string to its lowercase counterpart. `lowercase_string` is part of [mutate string](https://github.com/opensearch-project/data-prepper/tree/main/data-prepper-plugins/mutate-string-processors#mutate-string-processors) processors.

Option | Required | Type | Description
:--- | :--- | :--- | :---
with_keys | Yes | List | A list of keys to convert to lowercase.

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## Metrics

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