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

# map.removeKey

> Returns a copy of a map with a single specified key removed.

## Description

Creates a new map with a single specified key removed. The original map is not modified.

## Syntax

```cypher theme={null}
flex.map.removeKey(map, key)
```

## Parameters

| Parameter | Type   | Required | Description                    |
| --------- | ------ | -------- | ------------------------------ |
| `map`     | map    | Yes      | The map to remove the key from |
| `key`     | string | Yes      | The key to remove              |

## Returns

**Type:** map (object)

A new map containing all properties from the input map except the specified key. Returns an empty map if input is not a valid object.

## Examples

### Example 1: Basic Key Removal

```cypher theme={null}
WITH {name: 'Alice', age: 30, email: 'alice@example.com'} AS user
RETURN flex.map.removeKey(user, 'email') AS sanitized
```

**Output:**

```text theme={null}
sanitized
-----------------------
{name: 'Alice', age: 30}
```

### Example 2: Removing Sensitive Data

```cypher theme={null}
MATCH (u:User)
WITH properties(u) AS userProps
RETURN u.id, flex.map.removeKey(userProps, 'password') AS safeProps
```

### Example 3: Cleaning Response Data

```cypher theme={null}
MATCH (p:Product {id: 123})
WITH properties(p) AS props
WITH flex.map.removeKey(props, 'internalId') AS cleaned
RETURN cleaned AS product
```

### Example 4: Removing Non-Existent Key

```cypher theme={null}
WITH {a: 1, b: 2} AS map
RETURN flex.map.removeKey(map, 'c') AS result
```

**Output:**

```text theme={null}
result
---------
{a: 1, b: 2}
```

(Key doesn't exist, so map is returned unchanged)

## Notes

* Returns empty map if input is not a valid object or is `null`
* If key is `null`, returns a shallow copy of the map
* If the key doesn't exist, returns a copy with all original properties
* Creates a new map; does not modify the original
* Useful for sanitizing data, removing sensitive fields, or filtering properties

## See Also

* [map.removeKeys](/udfs/flex/map/removeKeys) - Remove multiple keys at once
* [map.submap](/udfs/flex/map/submap) - Keep only specific keys (inverse operation)
* [map.merge](/udfs/flex/map/merge) - Combine multiple maps

## Frequently Asked Questions

<AccordionGroup>
  <Accordion title="Does flex.map.removeKey modify the original map?">
    No. It returns a new map with the specified key removed, leaving the original unchanged.
  </Accordion>

  <Accordion title="What happens if the key does not exist?">
    The function returns a copy of the original map unchanged — no error is thrown.
  </Accordion>
</AccordionGroup>