I am trying to combine two data sets, one with daily values and one with weekly
values. SurveyData conatins environmental data collected on a daily basis.
sat.data contains satellite sea surface temperature that is an average of
satellite measurements over a six day period. I would like to combine the two
files so that my output file has the daily dates from SurveyData and the weekly
average from sat.data that corresponds to that day. I have written a loop that
does exactly what I want, but it takes a very long time. Is there a faster way
to do this? What I have so far is below.
Thanks,
Tim
#Compare dates
for(i in 1:length(SurveyData$Date))
{
print(i)
for(j in 1:length(sat.data$Date.Start))
{
if(
sat.data$Date.Start[j]<=SurveyData$Date[i] &
sat.data$Date.End[j]>=SurveyData$Date[i])
survey.data[i]<- sat.data$data[j]
}
}
#Create data frame with final data
final.data<-data.frame(SurveyData$Record,SurveyData$Date,survey.data)
#Write data to file
write.csv(final.data,file="Combined.csv")
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