Hi,
I have a file txt with the min / max temperature for each day and with this code ...
const x = msg.payload;
x.forEach(element => {
let data
let tempMin
let tempMax
msg.payload = (element.col1)
data = msg.payload.substr(0, 2)
msg.payload = (element.col1)
tempMin = msg.payload.substr(6, 4)
tempMax = (element.col2)
let arrayData = []
let arrayTempMin = []
let arrayTempMax = []
arrayData = flow.get('valueData') || []
arrayTempMin = flow.get('valueTempMin') || []
arrayTempMax = flow.get('valueTempMax') || []
arrayData.push(data)
arrayTempMin.push(tempMin)
arrayTempMax.push(tempMax)
flow.set("valueData", arrayData)
flow.set("valueTempMin", arrayTempMin)
flow.set("valueTempMax", arrayTempMax)
});
return msg;
(where x is the data from txt file), I set 3 array and send the value to a chart and it's works fine......
but the txt file has more 100 row and I'd like to select only the last 30 row.
It's all the morning I try to set this filter without success, can you help me?
(I found how to select the last item, but not the last (n) item ....)