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Unpack list

Unpack (extract) items from a column of lists into separate columns.

The first output column will contain the items in the first position of the input lists, the second column items in the second position etc.


The following are the step's expected inputs and outputs and their specific types.

Step signature
unpack_list(lists: list, {
    "param": value
}) -> (list_items: dataset)

where the object {"param": value} is optional in most cases and if present may contain any of the parameters described in the corresponding section below.


lists: column:list

An input column containing lists to unpack.


list_items: dataset

The output dataset containing list elements in individual columns.


start: integer = 0

List index of first element to extract.

Range: 0 ≤ start < inf

n_items: integer = 1

Total number of consecutive items to extract from lists.

Range: 1 ≤ n_items < inf

prefix: string | null

Prefix for names of generated columns. By default, will use the output dataset's name concatenated with "_0", "_1" etc. for the first extracted column, the second column etc. respectively. I.e. you name the output dataset of this step list_items, then its columns will be named "list_items_0", "list_items_1" etc. If a prefix is provided, this will be used instead of the output dataset's name.

column_names: array[string]

A list of names for the columns in the output dataset. Will be used only if the number of names passed matches the n_items parameter.

Items in column_names

item: string

The name of a single column in the ouput.