string
    The following is a list of functions in the category string
| Function | Description | 
|---|---|
| concat | Convert two or more values of any data type to string and return the concatenated result. A value with an undefined value is represented by '<undefined>'. | 
| string | Convert one or more values of any data type to string and return the concatenated result. A value with an undefined value is represented by '<undefined>'. | 
| url_decode | URL decode a value or bag of values. |