pearsonr() function

The pearsonr() function computes the Pearson R correlation coefficient between two streams by first joining the streams, then performing the covariance operation normalized to compute R.

*Function type: Transformation
**Output data type:* Float

pearsonr(x: stream1, y: stream2, on: ["_time", "_field"])

Parameters

x

First input stream used in the operation.

*Data type: Record*

y

Second input stream used in the operation.

*Data type: Record*

on

The list of columns on which to join.

*Data type: Array of strings*

Examples

stream1 = from(bucket:"example-bucket")
  |> range(start:-15m)
  |> filter(fn: (r) =>
    r._measurement == "mem" and
    r._field == "used"
  )
stream2 = from(bucket:"example-bucket")
  |> range(start:-15m)
  |> filter(fn: (r) => r
    ._measurement == "mem" and
    r._field == "available"
  )
pearsonr(x: stream1, y: stream2, on: ["_time"])

Function definition

pearsonr = (x,y,on) =>
  cov(x:x, y:y, on:on, pearsonr:true)