> ## Documentation Index
> Fetch the complete documentation index at: https://docs.xano.com/llms.txt
> Use this file to discover all available pages before exploring further.
# Manipulation
**NOTE**
When a filter below refers to the **parent value**, we're talking about the value box that lives immediately above the filter.
## fill
Create an array of a certain size with a default value.
| Parameter | Purpose | Example |
| ------------ | -------------------------------- | --------------- |
| parent value | The default value to fill | "default value" |
| start | The starting index of the array | 0 |
| length | The number of items in the array | 10 |
### Examples
```json theme={null}
[
"Default Value",
"Default Value",
"Default Value",
"Default Value",
"Default Value",
"Default Value",
"Default Value",
"Default Value",
"Default Value",
"Default Value"
]
```
***
## fill\_keys
Creates an object of a certain size with a default value and a list of keys.
| Parameter | Purpose | Example |
| ------------ | ------------------------- | --------------------------- |
| parent value | The default value to fill | "default value" |
| keys | The array of keys to use | `[ "key1", "key2", "key3"]` |
### Examples
```json theme={null}
{
"key1": "Default Value",
"key2": "Default Value",
"key3": "Default Value"
}
```
***
## first\_notempty
Applies the first value that is not **empty** (0, null, "", empty string)
Useful if you need to determine a value to apply based on what is provided, such as editing a database record and being uncertain if an input will be provided to replace a value.
| Parameter | Purpose | Example |
| ------------ | --------------------------------------------- | ----------------------------------- |
| parent value | The value to check if empty | Can contain any value, or no value. |
| value | The value to use if the parent value is empty | "default" |
### Examples
***
## first\_notnull
Applies the first value that is not `null`
Useful if you need to determine a value to apply based on what is provided, such as editing a database record and being uncertain if an input will be provided to replace a value.
**Hint**
Remember, `null` is its own value entirely. It is not the same as "null", an empty string, or any other similar empty state.
| Parameter | Purpose | Example |
| ------------ | ---------------------------------------------- | ---------------- |
| parent value | The value to check if `null` | Can be any value |
| value | The value to use if the parent value is `null` | "default" |
### Examples
***
## get
Gets a value at the specified path inside of an array or object.
For arrays, the path can be an index, such as `0`, `1,` or `2`, which will get the specific item at that index in the array.
For arrays of objects, you can specify the index + a path, such as `2.name`
For single objects, you can just specify the path, such as `name`.
This filter is useful if you aren't sure if the value you need will exist, and need to provide a default value in place of it.
**Hint**
Are you getting errors in your function stacks because certain values don't exist all the time? The **GET** filter can be a great fix for this.
| Parameter | Purpose | Example |
| ------------- | ----------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| parent value | The object or array to search for the value | This can be an object, array, a variable, or the result of one of the Get All Input functions [\[1\]](/the-function-stack/functions/utility-functions#get-all-input) [\[2\]](/the-function-stack/functions/utility-functions#get-all-raw-input) |
| path | The path to look for inside of the parent value | For getting a specific array item: `0` For getting a specific path inside of an object: `pathName` For getting a specific path inside of an array of objects: `0.pathName` |
| default value | The value to provide in place of the value that isn't found | This value can be whatever you'd like. |
### Examples
***
## has
Checks if a value is present (similar to get), but only returns a true or false.
| Parameter | Purpose | Example |
| ------------ | ----------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| parent value | The object or array to search for the value | This can be an object, array, a variable, or the result of one of the Get All Input functions [\[1\]](/the-function-stack/functions/utility-functions#get-all-input) [\[2\]](/the-function-stack/functions/utility-functions#get-all-raw-input) |
| path | The path to look for inside of the parent value | For getting a specific array item: `0`
For getting a specific path inside of an object: `pathName`
For getting a specific path inside of an array of objects: `0.pathName` |
### Examples
***
## set
Replaces or inserts new data at a specified path.
| Parameter | Purpose |
| ------------ | ------------------------------------------------- |
| parent value | The object or array to target with the set filter |
| path | The path at which to insert the supplied value |
| value | The supplied value to use |
### Examples
***
## set\_conditional
Use set\_conditional to set a new value in an object based on whether a condition evaluates as true.
| Parameter | Purpose |
| ------------ | ------------------------------------------------------------------------------------------------------------------------ |
| parent value | The data to insert the result, such as an object |
| path | The path to insert the result |
| value | The value to insert at the specified path |
| conditional | The condition to check. This can either come from an earlier function,or another filter that returns a `true` or `false` |
### Examples
***
## set\_ifnotempty
## set\_ifnotnull
Sets a new value in an object if the value provided is not empty. An empty value can be 0, `null`, or an empty string.
set\_ifnotnull works the same, but only checks for `null`
| Parameter | Purpose | Example |
| ------------ | ------------------------------------------------------------ | --------------------------------------- |
| parent value | Where to set the value | This will usually be an existing object |
| path | The path to set the value if the checked value exists | "name"
"age"
"location" |
| value | The value to set if the checked value is not empty (or null) | Any value |
### Examples
In this function stack, we're simulating a user submitting changes to their user profile.
***
## transform
The `transform` filter is universal way to transform data. It works with arrays, objects, and scalar values. It uses the [expression data type](/the-function-stack/data-types/expression) to specify the transformation.
## Hint
This filter is similar to the [map filter](/the-function-stack/filters/transform#map), except it can bind to all data - not just an array.
You can use the context variable \$\$ to target the parent value.
| Parameter | Purpose | Example |
| ------------ | ---------------------------------------- | ---------------------------- |
| parent value | The value to apply the transformation to | Can be any value or variable |
| expression | The expression to run | Any expression |
Read more about expressions and Xano Transform below.
Expression
Xano Transform
### Examples
```powershell theme={null}
[1,2,3]|transform:($$|count) // returns 3
[1,2,3]|transform:($$|count)+($$|sum) // returns 9
{first:Alpha,last:Beta}|transform:$$.first~" "~$$.last // returns Alpha Beta
```
***
## unset
Removes a key from an object
| Parameter | Purpose |
| ------------ | --------------------------------------------- |
| parent value | The object to target |
| path | The name of the key to remove from the object |
### Examples
***