[R] reply: help with loop

[Suman Pramanik]

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)