get

Gets a field from a record or an element from a list

get(x:record, field:string, [fallback:any]) -> any
get(x:record|list, index:number, [fallback:any]) -> any

Description

The get function returns the record field with the name field or the list element with the index index. If fallback is provided, the function gracefully returns the fallback value instead of emitting a warning and returning null.

xs: record|list

A record or list you want to access.

index: int/field: string

An index or field to access. If the function’s subject xs is a list, index refers to the position in the list. If the subject xs is a record, index refers to the field index. If the subject is a record, you can also use the fields name as a string to refer to it.

If the given index or field are do not exist in the subject and no fallback was provided, a warning will be raised and the function will return null.

fallback: any (optional)

A fallback value to return if the given index or field do not exist in the subject. Providing a fallback avoids a warning.

Examples

Get the first element of a list, or a fallback value

from (
  {xs: [1, 2, 3]},
  {xs: []},
}
select first = xs.get(0, -1)

{first: 1}
{first: -1}

Access a field of a record, or a fallback value

from (
  {x: 1, y: 2},
  {x: 3},
}
select x = this.get("x", -1), y = this.get("y", -1)

{x: 1, y: 2}
{x: 3, y: -1}

See Also

keys