Flux query by weekday 1

// Import Flux date package: https://docs.influxdata.com/influxdb/v2.0/reference/flux/stdlib/date/
import "date"
// Import Flux dictionary package: https://docs.influxdata.com/influxdb/v2.0/reference/flux/stdlib/dict/
import "dict"

bucket = "mybucket"

// Work with data collected in the past 5 minutes
start = -5m
stop = now()
measurement = "m0"
field = "f0"

// Create a dictionary of kwh measurements
kwh_by_day = [
  date.Sunday: 0.05,
  date.Monday: 0.03,
  date.Tuesday: 0.02,
  date.Wednesday: 0.01,
  date.Thursday: 0.15,
  date.Friday: 0.03,
  date.Saturday: 0.07,
]

// Query from our bucket defined above
from(bucket)
    // Query from our time range defined above
    |> range(start, stop)
    // Pull out our measurement and field defined above
    |> filter(fn: (r) => r._measurement == measurement and r._field == field)
    // For reach row r in the results, get today's day of week, and 
    // look up the kwh for today
    // append a column called cost that multiples the kwh hours and daily cost
    // map() documentation: https://docs.influxdata.com/influxdb/v2.0/reference/flux/stdlib/built-in/transformations/map/
    |> map(fn: (r) => {
      day = date.weekDay(t: r._time)
      kwh = dict.get(dict: kwh_by_day, key: day, default: 0.0)
      return {r with cost: kwh * r._value}
    })