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Do you expect a string to match this pattern?

Source: R/expect-match.R
expect_match.Rd

Do you expect a string to match this pattern?

Usage

expect_match(
  object,
  regexp,
  perl = FALSE,
  fixed = FALSE,
  ...,
  all = TRUE,
  info = NULL,
  label = NULL
)

expect_no_match(
  object,
  regexp,
  perl = FALSE,
  fixed = FALSE,
  ...,
  all = TRUE,
  info = NULL,
  label = NULL
)

Arguments

object

Object to test.

Supports limited unquoting to make it easier to generate readable failures within a function or for loop. See quasi_label for more details.

regexp

Regular expression to test against.

perl

logical. Should Perl-compatible regexps be used?

fixed

If TRUE, treats regexp as a string to be matched exactly (not a regular expressions). Overrides perl.

...

Arguments passed on to base::grepl

ignore.case

logical. if FALSE, the pattern matching is case sensitive and if TRUE, case is ignored during matching.

value

logical. If FALSE, a vector containing the (integer) indices of the matches determined by grep is returned, and if TRUE, a vector containing the matching elements themselves is returned.

useBytes

logical. If TRUE the matching is done byte-by-byte rather than character-by-character. See ‘Details’.

invert

logical. If TRUE return indices or values for elements that do not match.

replacement

a replacement for the matched pattern in sub and gsub. Coerced to character if possible. For fixed = FALSE this can include backreferences "\1" to "\9" to parenthesized subexpressions of pattern. For perl = TRUE only, it can also contain "\U" or "\L" to convert the rest of the replacement to upper or lower case and "\E" to end case conversion. If a character vector of length 2 or more is supplied, the first element is used with a warning. If NA, all elements in the result corresponding to matches will be set to NA.

all

Should all elements of actual value match regexp (TRUE), or does only one need to match (FALSE).

info

Extra information to be included in the message. This argument is soft-deprecated and should not be used in new code. Instead see alternatives in quasi_label.

label

Used to customise failure messages. For expert use only.

Details

expect_match() checks if a character vector matches a regular expression, powered by grepl().

expect_no_match() provides the complementary case, checking that a character vector does not match a regular expression.

Functions

  • expect_no_match(): Check that a string doesn't match a regular expression.

See also

Other expectations: comparison-expectations, equality-expectations, expect_error(), expect_length(), expect_named(), expect_null(), expect_output(), expect_reference(), expect_silent(), inheritance-expectations, logical-expectations

Examples

expect_match("Testing is fun", "fun")
expect_match("Testing is fun", "f.n")
expect_no_match("Testing is fun", "horrible")

show_failure(expect_match("Testing is fun", "horrible"))
#> Failed expectation:
#> Expected "Testing is fun" to match regexp "horrible".
#> Actual text:
#> ✖ │ Testing is fun
show_failure(expect_match("Testing is fun", "horrible", fixed = TRUE))
#> Failed expectation:
#> Expected "Testing is fun" to match string "horrible".
#> Actual text:
#> ✖ │ Testing is fun

# Zero-length inputs always fail
show_failure(expect_match(character(), "."))
#> Failed expectation:
#> Expected `character()` to have at least one element.