> ## 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
## fill
`value|fill:start:length`
```javascript theme={null}
0|fill:0:10 // Returns [0,0,0,0,0,0,0,0,0,0]
"x"|fill:2:5 // Returns [null,null,"x","x","x","x","x"]
true|fill:1:3 // Returns [null,true,true,true]
```
## fill\_keys
`value|fill_keys:keys`
```javascript theme={null}
"value"|fill_keys:["a","b","c"] // Returns {"a":"value","b":"value","c":"value"}
0|fill_keys:["x","y"] // Returns {"x":0,"y":0}
```
## first\_notempty
`value|first_notempty:default`
```javascript theme={null}
""|first_notempty:"default" // Returns "default"
"value"|first_notempty:"default" // Returns "value"
```
## first\_notnull
`value|first_notnull:default`
```javascript theme={null}
null|first_notnull:"default" // Returns "default"
"value"|first_notnull:"default" // Returns "value"
```
## get
`value|get:key:default`
```javascript theme={null}
{"name":"John"}|get:"name":"unknown" // Returns "John"
{}|get:"name":"unknown" // Returns "unknown"
```
## has
`value|has:key`
```javascript theme={null}
{"name":"John"}|has:"name" // Returns true
{"name":"John"}|has:"age" // Returns false
```
## set
`value|set:key:new_value`
```javascript theme={null}
{}|set:"name":"John" // Returns {"name":"John"}
{"age":30}|set:"name":"John" // Returns {"age":30,"name":"John"}
```
## set\_conditional
`value|set_conditional:key:new_value:condition`
```javascript theme={null}
{}|set_conditional:"status":"active":true // Returns {"status":"active"}
{}|set_conditional:"status":"active":false // Returns {}
```
## set\_ifnotempty
`value|set_ifnotempty:key:new_value`
```javascript theme={null}
{}|set_ifnotempty:"name":"" // Returns {}
{}|set_ifnotempty:"name":"John" // Returns {"name":"John"}
```
## set\_ifnotnull
`value|set_ifnotnull:key:new_value`
```javascript theme={null}
{}|set_ifnotnull:"name":null // Returns {}
{}|set_ifnotnull:"name":"John" // Returns {"name":"John"}
```
## transform
`value|transform:transformation`
```javascript theme={null}
2|transform:$$+3 // Returns 5
[{value:2},{value:5}]|transform:$$.value*2 // Returns [4,10]
```
## unset
`value|unset:key`
```javascript theme={null}
{"name":"John","age":30}|unset:"age" // Returns {"name":"John"}
{"name":"John"}|unset:"address" // Returns {"name":"John"}
```