Diagnostics and Quality Checks

Duplicate Check

Find Repeated IDs

Repeated identifiers can merge records incorrectly unless the policy is explicit.

Program

Play the script to change the duplicate policy and see the resulting action.

duplicate_check.R 
policy_index <- 
id <- c("A1", "B2", "A1", "C3")
policy <- c("ignore", "flag", "stop")[policy_index]
duplicate_id <- unique(id[duplicated(id)])
duplicate_count <- length(duplicate_id)
action <- if (duplicate_count == 0) "ok" else policy
label <- paste(action, duplicate_count, sep = ":")
cat(label, "\n", sep = "")

policy_index <- 
id <- c("A1", "B2", "A1", "C3")
policy <- c("ignore", "flag", "stop")[policy_index]
duplicate_id <- unique(id[duplicated(id)])
duplicate_count <- length(duplicate_id)
action <- if (duplicate_count == 0) "ok" else policy
label <- paste(action, duplicate_count, sep = ":")
cat(label, "\n", sep = "")

policy_index <- 
id <- c("A1", "B2", "A1", "C3")
policy <- c("ignore", "flag", "stop")[policy_index]
duplicate_id <- unique(id[duplicated(id)])
duplicate_count <- length(duplicate_id)
action <- if (duplicate_count == 0) "ok" else policy
label <- paste(action, duplicate_count, sep = ":")
cat(label, "\n", sep = "")
identifier An ID column should usually identify one record.
duplicate scan `duplicated(id)` marks repeated IDs after their first appearance.
policy The duplicate policy decides whether to ignore, flag, or stop.