Find the nth number before the mth occurrence of a pattern.

Given a string, a pattern and natural numbers n and m, find the nth number that comes before the mth occurrence of the pattern.

str_nth_number_before_mth(
  string,
  pattern,
  n,
  m,
  decimals = FALSE,
  leading_decimals = decimals,
  negs = FALSE,
  sci = FALSE,
  big_mark = "",
  leave_as_string = FALSE,
  commas = FALSE
)

str_nth_number_before_first(
  string,
  pattern,
  n,
  decimals = FALSE,
  leading_decimals = decimals,
  negs = FALSE,
  sci = FALSE,
  big_mark = "",
  leave_as_string = FALSE,
  commas = FALSE
)

str_nth_number_before_last(
  string,
  pattern,
  n,
  decimals = FALSE,
  leading_decimals = decimals,
  negs = FALSE,
  sci = FALSE,
  big_mark = "",
  leave_as_string = FALSE,
  commas = FALSE
)

str_first_number_before_mth(
  string,
  pattern,
  m,
  decimals = FALSE,
  leading_decimals = decimals,
  negs = FALSE,
  sci = FALSE,
  big_mark = "",
  leave_as_string = FALSE,
  commas = FALSE
)

str_last_number_before_mth(
  string,
  pattern,
  m,
  decimals = FALSE,
  leading_decimals = decimals,
  negs = FALSE,
  sci = FALSE,
  big_mark = "",
  leave_as_string = FALSE,
  commas = FALSE
)

str_first_number_before_first(
  string,
  pattern,
  decimals = FALSE,
  leading_decimals = decimals,
  negs = FALSE,
  sci = FALSE,
  big_mark = "",
  leave_as_string = FALSE,
  commas = FALSE
)

str_first_number_before_last(
  string,
  pattern,
  decimals = FALSE,
  leading_decimals = decimals,
  negs = FALSE,
  sci = FALSE,
  big_mark = "",
  leave_as_string = FALSE,
  commas = FALSE
)

str_last_number_before_first(
  string,
  pattern,
  decimals = FALSE,
  leading_decimals = decimals,
  negs = FALSE,
  sci = FALSE,
  big_mark = "",
  leave_as_string = FALSE,
  commas = FALSE
)

str_last_number_before_last(
  string,
  pattern,
  decimals = FALSE,
  leading_decimals = decimals,
  negs = FALSE,
  sci = FALSE,
  big_mark = "",
  leave_as_string = FALSE,
  commas = FALSE
)

Arguments

string

A character vector.

pattern

The pattern to look for.

The default interpretation is a regular expression, as described in stringi::about_search_regex.

To match a without regular expression (i.e. as a human would), use coll(). For details see stringr::regex().

n, m

Vectors of integerish values. Must be either length 1 or have length equal to the length of string. Negative indices count from the back: while 1 and 2 correspond to first and second, -1 and -2 correspond to last and second-last. 0 will return NA.

decimals

Do you want to include the possibility of decimal numbers (TRUE) or not (FALSE, the default).

leading_decimals

Do you want to allow a leading decimal point to be the start of a number?

negs

Do you want to allow negative numbers? Note that double negatives are not handled here (see the examples).

sci

Make the search aware of scientific notation e.g. 2e3 is the same as 2000.

big_mark

A character. Allow this character to be used as a thousands separator. This character will be removed from between digits before they are converted to numeric. You may specify many at once by pasting them together e.g. big_mark = ",_" will allow both commas and underscores. Internally, this will be used inside a [] regex block so e.g. "a-z" will behave differently to "az-". Most common separators (commas, spaces, underscores) should work fine.

leave_as_string

Do you want to return the number as a string (TRUE) or as numeric (FALSE, the default)?

commas

Deprecated. Use big_mark instead.

Value

A numeric or character vector.

See also

Other numeric extractors: str_extract_numbers(), str_nth_number_after_mth(), str_nth_number()

Examples

string <- c(
  "abc1abc2abc3abc4def5abc6abc7abc8abc9",
  "abc1def2ghi3abc4def5ghi6abc7def8ghi9"
)
str_nth_number_before_mth(string, "def", 1, 1)
#> [1] 1 1
str_nth_number_before_mth(string, "abc", 2, 3)
#> [1] 2 2
str_nth_number_before_first(string, "def", 2)
#> [1]  2 NA
str_nth_number_before_last(string, "def", -1)
#> [1] 4 7
str_first_number_before_mth(string, "abc", 2)
#> [1] 1 1
str_last_number_before_mth(string, "def", 1)
#> [1] 4 1
str_first_number_before_first(string, "def")
#> [1] 1 1
str_first_number_before_last(string, "def")
#> [1] 1 1
str_last_number_before_first(string, "def")
#> [1] 4 1
str_last_number_before_last(string, "def")
#> [1] 4 7