isEmpty - Check if array contains no elements

Returns true if the array is empty (contains no elements).

Syntax

Like many functions in DataPrime, isEmpty supports two notations, function and method notation. These interchangeable forms allow flexibility in how you structure expressions.

Function notation

isEmpty(array: array<T>): bool

Method notation

array: array<T>.isEmpty(): bool

Arguments

Name	Type	Required	Description
array	array of type T	true	T must be either `string`, `bool`, `number`, `interval`, `timestamp`, `regexp` or `enum`

Example - Basic usage

Checking if an array is empty is a simple method call against that array:

Function notation

create is_empty from  isEmpty(my_array)

Method notation

create is_empty from my_array.isEmpty()

This will produce a new field, is_empty which is a boolean value indicating if the array is or isn't empty.

Example - Shortcutting execution using isEmpty

If we want to perform some operation on our array, we can use isEmpty and if to optimize our query. Consider the following documents:

{
    "names": ["Chris", "John", "Ariel"]
},
{
    "names": []
}

If we wish to build a string from these values, we can save some cycles by checking if the array isEmpty and only continuing if it is:

create msg from if(!names.isEmpty(), names.arrayJoin(','), '')

Now arrayJoin is only invoked if the array value for names has any elements.

Try it yourself

Open up your explore screen and paste in the following command:

create names from ['Job 1', 'Job 2', 'Job 4']
| create msg from if(!names.isEmpty(), names.arrayJoin(','), '')

inArray

Next isSubset