create CV

Create a column-value data log item for a data value.

datalogger.createCV("", 0)

Data values that are written to the data log are assigned to a column in order to identify what their value is related to. Before logging a data value, it is formatted as a “CV” or “column-value” data item. A column name is attached to a data value this way.

A data log entry is written to the data log as an array of one or more “column-value” data item objects. This function creates the data item for the value you want to include in a log entry.

Parameters

• colunm: a string name that idenifies the data value.
• value: a data value of any type that is logged with the colunm name.

Example

Button states

Record the state of the buttons on the micro:bit every 500 milliseconds.

loops.everyInterval(500, function () {
    datalogger.logData([datalogger.createCV("Button A", input.buttonIsPressed(Button.A)), datalogger.createCV("Button B", input.buttonIsPressed(Button.B))])
})

Mood experiment

Create an experiment to record a person’s moods and relate them to current enviromental factors. Set 3 button options for moods of “happy”, “sad”, and “angry”. When the user signals their mood by pressing a button, read the current temperature, light level, and sound level to establish a relationship between those factors and mood.

input.onButtonPressed(Button.A, function () {
    logMood("happy")
})
function logMood (mood: string) {
    columns[0] = datalogger.createCV("mood", mood)
    columns[1] = datalogger.createCV("light", input.lightLevel())
    columns[2] = datalogger.createCV("sound", input.soundLevel())
    columns[3] = datalogger.createCV("temperature", input.temperature())
    datalogger.logData(columns)
}
input.onButtonPressed(Button.AB, function () {
    logMood("angry")
})
input.onButtonPressed(Button.B, function () {
    logMood("sad")
})
let columns: datalogger.ColumnValue[] = []
datalogger.setColumns([
"mood",
"light",
"sound",
"temperature"
])
columns = [
datalogger.createCV("", 0),
datalogger.createCV("", 0),
datalogger.createCV("", 0),
datalogger.createCV("", 0)
]

See also

log data, set columns

datalogger