R. Convert TimeStamp column from DataFrame to Date Format column-CodePudding

I have got a question.

There are a column with timestamp records like '1643410273'(summary more than 1.2M records). How can I transform it into Date format?

I created this code (R Language):

mydata <- read.csv("summary_dataset.csv")
unique(mydata$Callsign)
flight <- mydata[mydata$Callsign == "AFR228",]
AltitudeValue <- flight$Altitude
UTC_Timestamp <- flight$Timestamp
Flight_Date <- vector()

for (i in 1:length(UTC_Timestamp)){
  Flight_Date[i]=as.POSIXct(UTC_Timestamp[i], origin='1970-01-01', tz="UTC")
}

Flight_Date

But, in result, vector Flight_Date was filled Timestamp records. What's wrong?

CodePudding user response：

Convert the Timestamp column first to numeric, change it to POSIXct format by passing origin and extract only the date from it.

flight$Flight_Date <- as.Date(as.POSIXct(as.numeric(flight$Timestamp), 
                              origin='1970-01-01', tz="UTC"))

Example -

as.POSIXct(1643410273, origin='1970-01-01', tz="UTC")
#[1] "2022-01-28 22:51:13 UTC"

as.Date(as.POSIXct(1643410273, origin='1970-01-01', tz="UTC"))
#[1] "2022-01-28"