NEWS.md

stringr (development version)

• In str_replace_all(), a replacement function now receives all values in a single vector. This radically improves performance at the cost of breaking some existing uses (#462).

stringr 1.5.1

• Some minor documentation improvements.

• str_trunc() now correctly truncates strings when side is "left" or "center" (@UchidaMizuki, #512).

stringr 1.5.0

Breaking changes

• stringr functions now consistently implement the tidyverse recycling rules (#372). There are two main changes:

  • Only vectors of length 1 are recycled. Previously, (e.g.) str_detect(letters, c("x", "y")) worked, but it now errors.

  • str_c() ignores NULLs, rather than treating them as length 0 vectors.

  Additionally, many more arguments now throw errors, rather than warnings, if supplied the wrong type of input.

• regex() and friends now generate class names with stringr_ prefix (#384).

• str_detect(), str_starts(), str_ends() and str_subset() now error when used with either an empty string ("") or a boundary(). These operations didn't really make sense (str_detect(x, "") returned TRUE for all non-empty strings) and made it easy to make mistakes when programming.

New features

• Many tweaks to the documentation to make it more useful and consistent.

• New vignette("from-base") by @sastoudt provides a comprehensive comparison between base R functions and their stringr equivalents. It's designed to help you move to stringr if you're already familiar with base R string functions (#266).

• New str_escape() escapes regular expression metacharacters, providing an alternative to fixed() if you want to compose a pattern from user supplied strings (#408).

• New str_equal() compares two character vectors using unicode rules, optionally ignoring case (#381).

• str_extract() can now optionally extract a capturing group instead of the complete match (#420).

• New str_flatten_comma() is a special case of str_flatten() designed for comma separated flattening and can correctly apply the Oxford commas when there are only two elements (#444).

• New str_split_1() is tailored for the special case of splitting up a single string (#409).

• New str_split_i() extract a single piece from a string (#278, @bfgray3).

• New str_like() allows the use of SQL wildcards (#280, @rjpat).

• New str_rank() to complete the set of order/rank/sort functions (#353).

• New str_sub_all() to extract multiple substrings from each string.

• New str_unique() is a wrapper around stri_unique() and returns unique string values in a character vector (#249, @seasmith).

• str_view() uses ANSI colouring rather than an HTML widget (#370). This works in more places and requires fewer dependencies. It includes a number of other small improvements:

  • It no longer requires a pattern so you can use it to display strings with special characters.
  • It highlights unusual whitespace characters.
  • It's vectorised over both stringandpattern` (#407).
  • It defaults to displaying all matches, making str_view_all() redundant (and hence deprecated) (#455).

• New str_width() returns the display width of a string (#380).

• stringr is now licensed as MIT (#351).

Minor improvements and bug fixes

• Better error message if you supply a non-string pattern (#378).

• A new data source for sentences has fixed many small errors.

• str_extract() and str_exctract_all() now work correctly when pattern is a boundary().

• str_flatten() gains a last argument that optionally override the final separator (#377). It gains a na.rm argument to remove missing values (since it's a summary function) (#439).

• str_pad() gains use_width argument to control whether to use the total code point width or the number of code points as "width" of a string (#190).

• str_replace() and str_replace_all() can use standard tidyverse formula shorthand for replacement function (#331).

• str_starts() and str_ends() now correctly respect regex operator precedence (@carlganz).

• str_wrap() breaks only at whitespace by default; set whitespace_only = FALSE to return to the previous behaviour (#335, @rjpat).

• word() now returns all the sentence when using a negative start parameter that is greater or equal than the number of words. (@pdelboca, #245)

stringr 1.4.1

Hot patch release to resolve R CMD check failures.

stringr 1.4.0

• str_interp() now renders lists consistently independent on the presence of additional placeholders (@amhrasmussen).

• New str_starts() and str_ends() functions to detect patterns at the beginning or end of strings (@jonthegeek, #258).

• str_subset(), str_detect(), and str_which() get negate argument, which is useful when you want the elements that do NOT match (#259, @yutannihilation).

• New str_to_sentence() function to capitalize with sentence case (@jonthegeek, #202).

stringr 1.3.1

• str_replace_all() with a named vector now respects modifier functions (#207)

• str_trunc() is once again vectorised correctly (#203, @austin3dickey).

• str_view() handles NA values more gracefully (#217). I've also tweaked the sizing policy so hopefully it should work better in notebooks, while preserving the existing behaviour in knit documents (#232).

stringr 1.3.0

API changes

• During package build, you may see Error : object ‘ignore.case’ is not exported by 'namespace:stringr'. This is because the long deprecated str_join(), ignore.case() and perl() have now been removed.

New features

• str_glue() and str_glue_data() provide convenient wrappers around glue and glue_data() from the glue package (#157).

• str_flatten() is a wrapper around stri_flatten() and clearly conveys flattening a character vector into a single string (#186).

• str_remove() and str_remove_all() functions. These wrap str_replace() and str_replace_all() to remove patterns from strings. (@Shians, #178)

• str_squish() removes spaces from both the left and right side of strings, and also converts multiple space (or space-like characters) to a single space within strings (@stephlocke, #197).

• str_sub() gains omit_na argument for ignoring NA. Accordingly, str_replace() now ignores NAs and keeps the original strings. (@yutannihilation, #164)

Bug fixes and minor improvements

• str_trunc() now preserves NAs (@ClaytonJY, #162)

• str_trunc() now throws an error when width is shorter than ellipsis (@ClaytonJY, #163).

• Long deprecated str_join(), ignore.case() and perl() have now been removed.

stringr 1.2.0

API changes

• str_match_all() now returns NA if an optional group doesn't match (previously it returned ""). This is more consistent with str_match() and other match failures (#134).

New features

• In str_replace(), replacement can now be a function that is called once for each match and whose return value is used to replace the match.

• New str_which() mimics grep() (#129).

• A new vignette (vignette("regular-expressions")) describes the details of the regular expressions supported by stringr. The main vignette (vignette("stringr")) has been updated to give a high-level overview of the package.

Minor improvements and bug fixes

• str_order() and str_sort() gain explicit numeric argument for sorting mixed numbers and strings.

• str_replace_all() now throws an error if replacement is not a character vector. If replacement is NA_character_ it replaces the complete string with replaces with NA (#124).

• All functions that take a locale (e.g. str_to_lower() and str_sort()) default to "en" (English) to ensure that the default is consistent across platforms.

stringr 1.1.0

• Add sample datasets: fruit, words and sentences.

• fixed(), regex(), and coll() now throw an error if you use them with anything other than a plain string (#60). I've clarified that the replacement for perl() is regex() not regexp() (#61). boundary() has improved defaults when splitting on non-word boundaries (#58, @lmullen).

• str_detect() now can detect boundaries (by checking for a str_count() > 0) (#120). str_subset() works similarly.

• str_extract() and str_extract_all() now work with boundary(). This is particularly useful if you want to extract logical constructs like words or sentences. str_extract_all() respects the simplify argument when used with fixed() matches.

• str_subset() now respects custom options for fixed() patterns (#79, @gagolews).

• str_replace() and str_replace_all() now behave correctly when a replacement string contains $s, \\\\1, etc. (#83, #99).

• str_split() gains a simplify argument to match str_extract_all() etc.

• str_view() and str_view_all() create HTML widgets that display regular expression matches (#96).

• word() returns NA for indexes greater than number of words (#112).

stringr 1.0.0

• stringr is now powered by stringi instead of base R regular expressions. This improves unicode and support, and makes most operations considerably faster. If you find stringr inadequate for your string processing needs, I highly recommend looking at stringi in more detail.

• stringr gains a vignette, currently a straight forward update of the article that appeared in the R Journal.

• str_c() now returns a zero length vector if any of its inputs are zero length vectors. This is consistent with all other functions, and standard R recycling rules. Similarly, using str_c("x", NA) now yields NA. If you want "xNA", use str_replace_na() on the inputs.

• str_replace_all() gains a convenient syntax for applying multiple pairs of pattern and replacement to the same vector:

  input <- c("abc", "def")
  str_replace_all(input, c("[ad]" = "!", "[cf]" = "?"))

• str_match() now returns NA if an optional group doesn't match (previously it returned ""). This is more consistent with str_extract() and other match failures.

• New str_subset() keeps values that match a pattern. It's a convenient wrapper for x[str_detect(x)] (#21, @jiho).

• New str_order() and str_sort() allow you to sort and order strings in a specified locale.

• New str_conv() to convert strings from specified encoding to UTF-8.

• New modifier boundary() allows you to count, locate and split by character, word, line and sentence boundaries.

• The documentation got a lot of love, and very similar functions (e.g. first and all variants) are now documented together. This should hopefully make it easier to locate the function you need.

• ignore.case(x) has been deprecated in favour of fixed|regex|coll(x, ignore.case = TRUE), perl(x) has been deprecated in favour of regex(x).

• str_join() is deprecated, please use str_c() instead.

stringr 0.6.2

• fixed path in str_wrap example so works for more R installations.

• remove dependency on plyr

stringr 0.6.1

• Zero input to str_split_fixed returns 0 row matrix with n columns

• Export str_join

stringr 0.6

• new modifier perl that switches to Perl regular expressions

• str_match now uses new base function regmatches to extract matches - this should hopefully be faster than my previous pure R algorithm

stringr 0.5

• new str_wrap function which gives strwrap output in a more convenient format

• new word function extract words from a string given user defined separator (thanks to suggestion by David Cooper)

• str_locate now returns consistent type when matching empty string (thanks to Stavros Macrakis)

• new str_count counts number of matches in a string.

• str_pad and str_trim receive performance tweaks - for large vectors this should give at least a two order of magnitude speed up

• str_length returns NA for invalid multibyte strings

• fix small bug in internal recyclable function

stringr 0.4

• all functions now vectorised with respect to string, pattern (and where appropriate) replacement parameters
• fixed() function now tells stringr functions to use fixed matching, rather than escaping the regular expression. Should improve performance for large vectors.
• new ignore.case() modifier tells stringr functions to ignore case of pattern.
• str_replace renamed to str_replace_all and new str_replace function added. This makes str_replace consistent with all functions.
• new str_sub<- function (analogous to substring<-) for substring replacement
• str_sub now understands negative positions as a position from the end of the string. -1 replaces Inf as indicator for string end.
• str_pad side argument can be left, right, or both (instead of center)
• str_trim gains side argument to better match str_pad
• stringr now has a namespace and imports plyr (rather than requiring it)

stringr 0.3

• fixed() now also escapes |
• str_join() renamed to str_c()
• all functions more carefully check input and return informative error messages if not as expected.
• add invert_match() function to convert a matrix of location of matches to locations of non-matches
• add fixed() function to allow matching of fixed strings.

stringr 0.2

• str_length now returns correct results when used with factors
• str_sub now correctly replaces Inf in end argument with length of string
• new function str_split_fixed returns fixed number of splits in a character matrix
• str_split no longer uses strsplit to preserve trailing breaks