R: Extract the 'n'th number from a string.

str_nth_number {strex}

R Documentation

Extract the `n`th number from a string.

Description

Extract the nth number from a string, where decimals, scientific notation and commas (as separators, not as an alternative to the decimal point) are optionally allowed.

Usage

str_nth_number(
  string,
  n,
  decimals = FALSE,
  leading_decimals = decimals,
  negs = FALSE,
  sci = FALSE,
  commas = FALSE,
  leave_as_string = FALSE
)

str_first_number(
  string,
  decimals = FALSE,
  leading_decimals = decimals,
  negs = FALSE,
  sci = FALSE,
  commas = FALSE,
  leave_as_string = FALSE
)

str_last_number(
  string,
  decimals = FALSE,
  leading_decimals = decimals,
  negs = FALSE,
  sci = FALSE,
  commas = FALSE,
  leave_as_string = FALSE
)

Arguments

`string`	A string.
`n`	A vector of integerish values. Must be either length 1 or have length equal to the length of `string`. Negative indices count from the back: while `n = 1` and `n = 2` correspond to first and second, `n = -1` and `n = -2` correspond to last and second-last. `n = 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.
`commas`	Allow comma separators in numbers (i.e. interpret 1,100 as a single number (one thousand one hundred) rather than two numbers (one and one hundred)).
`leave_as_string`	Do you want to return the number as a string (`TRUE`) or as numeric (`FALSE`, the default)?

Details

str_first_number(...) is just str_nth_number(..., n = 1).
str_last_number(...) is just str_nth_number(..., n = -1).

For a detailed explanation of the number extraction, see str_extract_numbers().

Value

A numeric vector (or a character vector if leave_as_string = TRUE).

Examples

strings <- c(
  "abc123def456", "abc-0.12def.345", "abc.12e4def34.5e9",
  "abc1,100def1,230.5", "abc1,100e3,215def4e1,000"
)
str_nth_number(strings, n = 2)
str_nth_number(strings, n = -2, decimals = TRUE)
str_first_number(strings, decimals = TRUE, leading_decimals = TRUE)
str_last_number(strings, commas = TRUE)
str_nth_number(strings,
  n = 1, decimals = TRUE, leading_decimals = TRUE,
  sci = TRUE
)
str_first_number(strings,
  decimals = TRUE, leading_decimals = TRUE,
  sci = TRUE, commas = TRUE, negs = TRUE
)
str_last_number(strings,
  decimals = TRUE, leading_decimals = FALSE,
  sci = FALSE, commas = TRUE, negs = TRUE, leave_as_string = TRUE
)
str_first_number(c("22", "1.2.3"), decimals = TRUE)

[Package strex version 1.4.2 Index]

Extract the nth number from a string.