Check the following code, it should work and solve your problem.
# function is.err returns 1 if criteria for erroneous entry are met,
else returns 0 for each district.
is.err <- function(df) { # df = data frame with entries for 1 district
with(df, {
C <- C[!is.na(C)] # C is the counts with any missing data out of it.
C1 <- c(NA, C) # C1 is the shifted C vector by q position
dif.C.C1 <- abs(C1-c(C,NA)) # absolute value of difference
between entry in C and next entry in C1
dif.C.C1 <- dif.C.C1[!is.na(dif.C.C1)] # removes all NA
p.C.C1 <- dif.C.C1/C[1:length(dif.C.C1)] # calculates proportion
if (any(dif.C.C1 > 5) & any(p.C.C1 > 0.5)){ # checks the criteria
e <- 1
}
else {
e <- 0
}
return(e)
})
}
# main function gets the value of erroneous entries by districts by
entering data of each district into is.err function and returns a data
frame showing status 0: if no error and 1: if error and corresponding
district
main <- function(df.main) {
with(df.main, {
#browser()
d <- unique(df.main$D)
r <- rep(100,length(d))
for (i in 1:length(d)) {
r[i] <- is.err(df.main[df.main$D == d[i],])
}
return(data.frame(D=d, r=r))
})
}
# first load the above code into R console and then run the lines
below, check ret. you should get result.
df <-
data.frame(D=c(rep("a",3),rep("b",3),rep("c",3)),Y=rep(c(2005:2007),3),C=c(10,0,9,1,0,1,5,NA,4))
ret <- main(df)