stringi: Fast and Portable Character String Processing in R

stringi (pronounced “stringy”, IPA [strinɡi]) is THE R package for very fast, portable, correct, consistent, and convenient string/text processing in any locale or character encoding.

Thanks to ICU, stringi fully supports a wide range of Unicode standards (see also this video).

stri_extract_all(regex="\\p{Emoji}",
    c("歡迎 欢迎! Χαίρετε! Bienvenidos! 😃❤🌍", "spam, spam, 🥓, 🍳, and spam"))
## [[1]]
## [1] "😃" "❤"  "🌍"
##
## [[2]]
## [1] "🥓" "🍳"

stri_count_fixed("ACATGAACGGGTACACACTG", "ACA", overlap=TRUE)
## [1] 3

stri_sort(c("cudný", "chladný", "hladný", "čudný"), locale="sk_SK")
## [1] "cudný"   "čudný"   "hladný"  "chladný"

stringi provides you with plenty of functions related to data cleansing, information extraction, and natural language processing:

• string concatenation, padding, wrapping, and substring extraction,

• pattern searching (e.g., with ICU Java-like regular expressions),

• collation, sorting, and ranking,

• random string generation,

• string transliteration, case mapping and folding,

• Unicode normalisation,

• date-time formatting and parsing,

and many more.

stringi is among the most often downloaded R packages.

You can obtain it from CRAN by calling:

install.packages("stringi")

stringi’s source code is hosted on GitHub. It is distributed under the open source BSD-3-clause license.

The package’s API was inspired by that of the early (pre-tidyverse; v0.6.2) version of Hadley Wickham’s stringr package (and since the 2015 v1.0.0 stringr is powered by stringi). Moreover, Hadley suggested quite a few new package features. The contributions from Bartłomiej Tartanus and many others is greatly appreciated. Thanks!

See also: stringx – a set of wrappers around stringi with a base R-compatible API.

Note

To learn more about R, check out Marek’s open-access (free!) textbook Deep R Programming [Gag23].

Citation: Gagolewski M., stringi: Fast and portable character string processing in R, Journal of Statistical Software 103(2), 2022, 1–59, doi:10.18637/jss.v103.i02.

Tutorial

• General Design Principles
  • Naming
  • Vectorisation
  • Acting Elementwise with Recycling
  • Missing Values
  • Data Flow
  • Further Deviations from Base R
• Basic String Operations
  • Computing Length and Width
  • Joining
  • Extracting and Replacing Substrings
• Code-Pointwise Comparing
  • Testing for Equality of Strings
  • Searching for Fixed Strings
  • Counting Matches
  • Search Engine Options
  • Detecting and Subsetting Patterns
  • Locating and Extracting Patterns
  • Replacing Pattern Occurrences
  • Splitting
• Regular Expressions
  • Matching Individual Characters
  • Alternating and Grouping Subexpressions
  • Quantifiers
  • Capture Groups and References Thereto
  • Anchoring
• Collation
  • Locales
  • Testing String Equivalence
  • Linear Ordering of Strings
  • Collator Options
  • Searching for Fixed Strings Revisited
• Other Operations
  • Analysing Text Boundaries
  • Trimming, Padding, and Other Formatting
  • Generating Random Strings
  • Transliterating
  • Parsing and Formatting Date and Time
• Input and Output
  • Dealing with Unicode Code Points
  • Character Encodings
  • Reading and Writing Text Files
  • Detecting Encodings
  • Converting Between Encodings
  • Normalising Strings
• Example Use Case: Data Preparation

Reference Manual

• R Package stringi Reference
  • about_arguments:
  • about_encoding:
  • about_locale:
  • about_search_boundaries:
  • about_search_charclass:
  • about_search_coll:
  • about_search_fixed:
  • about_search_regex:
  • about_search: String Searching
  • about_stringi: Fast and Portable Character String Processing in R
  • operator_add: Concatenate Two Character Vectors
  • operator_compare: Compare Strings with or without Collation
  • operator_dollar: as a Binary Operator
  • stri_compare: Compare Strings with or without Collation
  • stri_count_boundaries: Count the Number of Text Boundaries
  • stri_count: Count the Number of Pattern Occurrences
  • stri_datetime_add: Date and Time Arithmetic
  • stri_datetime_create: Create a Date-Time Object
  • stri_datetime_fields: Get Values for Date and Time Fields
  • stri_datetime_format: Date and Time Formatting and Parsing
  • stri_datetime_fstr: -Style Format Strings
  • stri_datetime_now: Get Current Date and Time
  • stri_datetime_symbols: List Localizable Date-Time Formatting Data
  • stri_detect: Detect Pattern Occurrences
  • stri_dup: Duplicate Strings
  • stri_duplicated: Determine Duplicated Elements
  • stri_enc_detect: Detect Character Set and Language
  • stri_enc_detect2: [DEPRECATED] Detect Locale-Sensitive Character Encoding
  • stri_enc_fromutf32: Convert From UTF-32
  • stri_enc_info: Query a Character Encoding
  • stri_enc_isascii: Check If a Data Stream Is Possibly in ASCII
  • stri_enc_isutf16: Check If a Data Stream Is Possibly in UTF-16 or UTF-32
  • stri_enc_isutf8: Check If a Data Stream Is Possibly in UTF-8
  • stri_enc_list: List Known Character Encodings
  • stri_enc_mark: Get Declared Encodings of Each String
  • stri_enc_set:
  • stri_enc_toascii: Convert To ASCII
  • stri_enc_tonative: Convert Strings To Native Encoding
  • stri_enc_toutf32: Convert Strings To UTF-32
  • stri_enc_toutf8: Convert Strings To UTF-8
  • stri_encode: Convert Strings Between Given Encodings
  • stri_escape_unicode: Escape Unicode Code Points
  • stri_extract_boundaries: Extract Data Between Text Boundaries
  • stri_extract: Extract Pattern Occurrences
  • stri_flatten: Flatten a String
  • stri_info:
  • stri_isempty: Determine if a String is of Length Zero
  • stri_join_list: Concatenate Strings in a List
  • stri_join: Concatenate Character Vectors
  • stri_length: Count the Number of Code Points
  • stri_list2matrix: Convert a List to a Character Matrix
  • stri_locale_info: Query Given Locale
  • stri_locale_list: List Available Locales
  • stri_locale_set:
  • stri_locate_boundaries: Locate Text Boundaries
  • stri_locate: Locate Pattern Occurrences
  • stri_match: Extract Regex Pattern Matches, Together with Capture Groups
  • stri_na2empty: Replace NAs with Empty Strings
  • stri_numbytes: Count the Number of Bytes
  • stri_opts_brkiter: Generate a List with BreakIterator Settings
  • stri_opts_collator: Generate a List with Collator Settings
  • stri_opts_fixed: Generate a List with Fixed Pattern Search Engine’s Settings
  • stri_opts_regex: Generate a List with Regex Matcher Settings
  • stri_order: Ordering Permutation
  • stri_pad: Pad (Center/Left/Right Align) a String
  • stri_rand_lipsum: A Lorem Ipsum Generator
  • stri_rand_shuffle: Randomly Shuffle Code Points in Each String
  • stri_rand_strings: Generate Random Strings
  • stri_rank: Ranking
  • stri_read_lines: Read Text Lines from a Text File
  • stri_read_raw: Read Text File as Raw
  • stri_remove_empty: Remove All Empty Strings from a Character Vector
  • stri_replace_na: Replace Missing Values in a Character Vector
  • stri_replace_rstr: Convert gsub-Style Replacement Strings
  • stri_replace: Replace Pattern Occurrences
  • stri_reverse: Reverse Each String
  • stri_sort_key: Sort Keys
  • stri_sort: String Sorting
  • stri_split_boundaries: Split a String at Text Boundaries
  • stri_split_lines: Split a String Into Text Lines
  • stri_split: Split a String By Pattern Matches
  • stri_sprintf: Format Strings
  • stri_startsendswith: Determine if the Start or End of a String Matches a Pattern
  • stri_stats_general: General Statistics for a Character Vector
  • stri_stats_latex: Statistics for a Character Vector Containing LaTeX Commands
  • stri_sub_all: Extract or Replace Multiple Substrings
  • stri_sub: Extract a Substring From or Replace a Substring In a Character Vector
  • stri_subset: Select Elements that Match a Given Pattern
  • stri_timezone_info: Query a Given Time Zone
  • stri_timezone_list: List Available Time Zone Identifiers
  • stri_timezone_set:
  • stri_trans_casemap: Transform Strings with Case Mapping or Folding
  • stri_trans_char: Translate Characters
  • stri_trans_general: General Text Transforms, Including Transliteration
  • stri_trans_list: List Available Text Transforms and Transliterators
  • stri_trans_nf: Perform or Check For Unicode Normalization
  • stri_trim: Trim Characters from the Left and/or Right Side of a String
  • stri_unescape_unicode: Un-escape All Escape Sequences
  • stri_unique: Extract Unique Elements
  • stri_width: Determine the Width of Code Points
  • stri_wrap: Word Wrap Text to Format Paragraphs
  • stri_write_lines: Write Text Lines to a Text File

Other

• Deep R Programming
• stringx
• JStatSoft Paper
• C++ API — Rcpp Example
• Changelog
• References