sd.append()

sd.append(filename, data)

Appends a string to a file on the memory card, creating the file if needed.

Appends data to filename on the memory card. Convert numbers and objects with string() first, and terminate lines with "\n" yourself.

Pair with datetime().epoch for timestamped log lines.

Name	Type	Required	Default	Description
filename	string	yes	—	File name on the memory card, e.g. `"log.txt"`.
data	string	yes	—	Text to append. Use `string()` to convert numbers/objects.

number 0 = no error, >0 = error code

// Timestamped log line: 1589247811:    ch3: 23.454
sd.append('log.txt', string(datetime().epoch) + ":    ch3: " + string(23.454) + "\n");