findColumn() function
The findColumn()
function returns an array of values in a specified column from the
first table in a stream of tables where the group key values match the specified predicate.
The function returns an empty array if no table is found or if the column label
is not present in the set of columns.
findColumn(
fn: (key) => key._field == "fieldName",
column: "_value",
)
Parameters
fn
A predicate function for matching keys in a table’s group key.
Expects a key
argument that represents a group key in the input stream.
column
Name of the column to extract.
tables
Input data.
Default is piped-forward data (<-
).
Example
The following example uses data provided by the sampledata
package
to show how findColumn()
transforms data.
import "sampledata"
sampledata.int()
|> findColumn(fn: (key) => key.tag == "t1", column: "_value")
// Returns [-2, 10, 7, 17, 15, 4]
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