regex

[andrewallenbruce]

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[andrewallenbruce]

If the prefix length varies and you want to dynamically determine the prefix for grouping, use a more flexible approach. Find the longest common prefix for each group:

longest_common_prefix <- \(strings) {
  if (length(strings) == 0) return("")
  prefix <- strings[1]
  for (string in strings) {
    while (substring(string, 1, nchar(prefix)) != prefix) {
      prefix <- substring(prefix, 1, nchar(prefix) - 1)
      if (nchar(prefix) == 0) return("")
    }
  }
  return(prefix)
}

group_by_variable_prefix <- function(char_vectors) {
  groups <- list()
  while (length(char_vectors) > 0) {
    # Find the longest common prefix for the remaining vectors
    lcp <- longest_common_prefix(char_vectors)
    
    # Group vectors that start with the longest common prefix
    group <- char_vectors[startsWith(char_vectors, lcp)]
    
    # Add the group to the list of groups
    groups <- c(groups, list(group))
    
    # Remove the grouped vectors from the original vector
    char_vectors <- char_vectors[!startsWith(char_vectors, lcp)]
  }
  return(groups)
}

# Example usage
char_vectors <- c("apple", "apply", "ape", "banana", "bandana", "band")
groups <- group_by_variable_prefix(char_vectors)
print(groups)

[andrewallenbruce]

Simple Diagram Methods

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