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Extracts all valid CASRNs from a character vector

Source: R/util_cas.R
extract_cas.Rd

This function searches for and extracts all valid Chemical Abstracts Service Registry Numbers (CASRNs) from a character vector. It uses a flexible pattern to find candidate strings (including those without hyphens) and then validates each one using the as_cas() coercion and validation function.

Usage

extract_cas(x)

Arguments

x

A character vector of text to be searched.

Value

A list of character vectors. Each element of the list corresponds to an element of the input x and contains all valid CASRNs found. An empty character(0) vector indicates no valid CASRNs were found for that input string.

See also

as_cas() and is_cas() for the underlying coercion and validation logic.

Examples

text <- c(
  "The CAS for formaldehyde is 50-00-0, and water is 7732-18-5.",
  "An invalid number is 50-00-1, but a padded one is 007732-18-5.",
  "No hyphens: 50000.",
  "No valid CASRNs in this string.",
  NA
)
extract_cas(text)
#> [[1]]
#> [1] "50-00-0"   "7732-18-5"
#> 
#> [[2]]
#> [1] "7732-18-5"
#> 
#> [[3]]
#> [1] "50-00-0"
#> 
#> [[4]]
#> character(0)
#> 
#> [[5]]
#> character(0)
#> 
# [[1]]
# [1] "50-00-0"   "7732-18-5"
#
# [[2]]
# [1] "7732-18-5"
#
# [[3]]
# [1] "50-00-0"
#
# [[4]]
# character(0)
#
# [[5]]
# character(0)