drop() function
The drop()
function removes specified columns from a table. Columns are specified either through a list or a predicate function. When a dropped column is part of the group key, it will be removed from the key. If a specified column is not present in a table, it will return an error.
*Function type: Transformation
**Output data type:* Record
drop(columns: ["col1", "col2"])
// OR
drop(fn: (column) => column =~ /usage*/)
Parameters
Make sure fn
parameter names match each specified parameter. To learn why, see Match parameter names.
columns
Columns to be removed from the table. Cannot be used with fn
.
*Data type: Array of strings*
fn
A predicate function which takes a column name as a parameter (column
) and returns a boolean indicating whether or not the column should be removed from the table. Cannot be used with columns
.
*Data type: Function*
Examples
Drop a list of columns
from(bucket: "example-bucket")
|> range(start: -5m)
|> drop(columns: ["host", "_measurement"])
Drop columns matching a predicate
from(bucket: "example-bucket")
|> range(start: -5m)
|> drop(fn: (column) => column =~ /usage*/)