keep() function
The keep()
function returns a table containing only the specified columns, ignoring all others.
Only columns in the group key that are also specified in the keep()
function will be kept in the resulting group key.
It is the inverse of drop
.
keep(columns: ["col1", "col2"])
// OR
keep(fn: (column) => column =~ /inodes*/)
Parameters
Make sure fn
parameter names match each specified parameter. To learn why, see Match parameter names.
columns
Columns that should be included in the resulting table.
Cannot be used with fn
.
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 included in the resulting table.
Cannot be used with columns
.
tables
Input data.
Default is piped-forward data (<-
).
Examples
The following examples use data provided by the sampledata
package
to show how keep()
transforms data.
Keep a list of columns
import "sampledata"
sampledata.int()
|> keep(columns: ["_time", "_value"])
Keep columns matching a predicate
import "sampledata"
sampledata.int()
|> keep(fn: (column) => column =~ /^_?t/)
Was this page helpful?
Thank you for your feedback!
Support and feedback
Thank you for being part of our community! We welcome and encourage your feedback and bug reports for Flux and this documentation. To find support, use the following resources:
InfluxDB Cloud customers can contact InfluxData Support.