Module 11 Debugging Assignment

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tukey_multiple <- function(x) {
  outliers <- array(TRUE, dim = dim(x))
  for (j in 1:ncol(x)) {
    outliers[, j] <- outliers[, j] && tukey.outlier(x[, j])
  }
  outlier.vec <- vector("logical", length = nrow(x))
  for (i in 1:nrow(x)) {
    outlier.vec[i] <- all(outliers[i, ])
  }
  return(outlier.vec)
}

set.seed(123)
test_mat <- matrix(rnorm(50), nrow = 10)
tukey_multiple(test_mat)


corrected_tukey <- function(x) {
  outliers <- array(TRUE, dim = dim(x))
  for (j in seq_len(ncol(x))) {
    # FIX: use element-wise '&' instead of scalar '&&'
    outliers[, j] <- outliers[, j] & tukey.outlier(x[, j])
  }
  outlier.vec <- logical(nrow(x))
  for (i in seq_len(nrow(x))) {
    outlier.vec[i] <- all(outliers[i, ])
  }
  outlier.vec
}

corrected_tukey(test_mat)









https://github.com/shanzay28/r-programming-assignments/blob/main/module11_debug.R


Bug & Error (reproduced): Running the original tukey_multiple(test_mat) fails with

Error in outliers[, j] && tukey.outlier(x[, j]) : 'length = 10' in coercion to 'logical(1)'.

Diagnosis: The loop used &&, which is a scalar logical operator (evaluates only the first element). We need an element-wise operation across the whole column, so the correct operator is &.

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