dfr <- read.delim("d:/readings.txt", colClasses=c("character", rep(c("numeric", "integer"), 24)))
dates <- strptime(dfr[,1], "%Y-%m-%d")


dfr[which(is.na(dfr))]


dates[duplicated(dates)]


flags <- as.matrix(dfr[,seq(3,49,2)])>0
sum(apply(flags, 1, all))