String Processing in R
Martin Schweinberger
Introduction
This tutorial introduces string processing and this can be used when working with language data. The entire code for the sections below can be downloaded here.
Preparation and session set up
This tutorial is based on R. If you have not installed R or are new to it, you will find an introduction to and more information how to use R here. For this tutorials, we need to install certain packages from an R library so that the scripts shown below are executed without errors. Before turning to the code below, please install the packages by running the code below this paragraph. If you have already installed the packages mentioned below, then you can skip ahead ignore this section. To install the necessary packages, simply run the following code - it may take some time (between 1 and 5 minutes to install all of the packages so you do not need to worry if it takes some time).
# install packages
install.packages("tidyverse")
# install klippy for copy-to-clipboard button in code chunks
remotes::install_github("rlesur/klippy")Now that we have installed the packages, we can activate them as shown below.
# set options
options(stringsAsFactors = F) # no automatic data transformation
options("scipen" = 100, "digits" = 4) # suppress math annotation
# load packages for website
library(tidyverse)
# activate klippy for copy-to-clipboard button
klippy::klippy()Once you have installed R-Studio and initiated the session by executing the code shown above, you are good to go.
Base String Processing
Before we start with string processing, we will load some example texts on which we will perform the processing.
# read in text
exampletext <- base::readRDS(url("https://slcladal.github.io/data/tx1.rda", "rb"))
# inspect
exampletext## [1] "Grammar is a system of rules which governs the production and use of utterances in a given language. These rules apply to sound as well as meaning, and include componential subsets of rules, such as those pertaining to phonology (the organisation of phonetic sound systems), morphology (the formation and composition of words), and syntax (the formation and composition of phrases and sentences). Many modern theories that deal with the principles of grammar are based on Noam Chomsky's framework of generative linguistics."This first example text represents a paragraph about grammar.
# read in text
splitexampletext <- base::readRDS(url("https://slcladal.github.io/data/tx2.rda", "rb"))
# inspect
splitexampletext## [1] "Grammar is a system of rules which governs the production and use of utterances in a given language."
## [2] "These rules apply to sound as well as meaning, and include componential subsets of rules, such as those pertaining to phonology (the organisation of phonetic sound systems), morphology (the formation and composition of words), and syntax (the formation and composition of phrases and sentences)."
## [3] "Many modern theories that deal with the principles of grammar are based on Noam Chomsky's framework of generative linguistics."This second example text represents the same paragraph about grammar, but split into individual sentences.
additionaltext <- base::readRDS(url("https://slcladal.github.io/data/tx3.rda", "rb"))
# inspect
additionaltext## [1] "In the early 20th century, Ferdinand de Saussure distinguished between the notions of langue and parole in his formulation of structural linguistics. According to him, parole is the specific utterance of speech, whereas langue refers to an abstract phenomenon that theoretically defines the principles and system of rules that govern a language. This distinction resembles the one made by Noam Chomsky between competence and performance in his theory of transformative or generative grammar. According to Chomsky, competence is an individual's innate capacity and potential for language (like in Saussure's langue), while performance is the specific way in which it is used by individuals, groups, and communities (i.e., parole, in Saussurean terms). "The third example text represents a paragraph about Ferdinand de Saussure - the founder of modern linguistics.
sentences <- base::readRDS(url("https://slcladal.github.io/data/tx4.rda", "rb"))
# inspect
sentences## [1] "This is a first sentence." "This is a second sentence."
## [3] "And this is a third sentence."The third example text consist of 3 short plain sentences.
In the following, we will perform various operations on the example text using only in-build, or base, functions.
The function substr extracts a substring from the text by position (position is the character position, i.e. the first character has position 1, the second character position 2, etc.).
# extract substring by position
substr(exampletext, start=14, stop=30)## [1] "system of rules w"The function grep informs whether a pattern is present in a text (or in a series of texts) with 1 indicating yes and 0 indicating no.
# find substring
grep("language", splitexampletext, value=FALSE, ignore.case=FALSE, fixed=FALSE)## [1] 1When the argument value is set to TRUE, grep returns the element in which the match occurs but not the elements in which is does not occur.
# find substring
grep("language", splitexampletext, value=TRUE, ignore.case=FALSE, fixed=FALSE)## [1] "Grammar is a system of rules which governs the production and use of utterances in a given language."The function grepl returns a logical vector with TRUE if the pattern occurs in the string and FALSE if the pattern does not occur in the string.
# find substring
grepl("language", splitexampletext, ignore.case=FALSE, fixed=FALSE)## [1] TRUE FALSE FALSEThe function sub replaces the first(!) occurrence of a pattern with another pattern in a given text.
sub("and", "AND", exampletext, ignore.case=FALSE, fixed=FALSE)## [1] "Grammar is a system of rules which governs the production AND use of utterances in a given language. These rules apply to sound as well as meaning, and include componential subsets of rules, such as those pertaining to phonology (the organisation of phonetic sound systems), morphology (the formation and composition of words), and syntax (the formation and composition of phrases and sentences). Many modern theories that deal with the principles of grammar are based on Noam Chomsky's framework of generative linguistics."The function gsub replaces all occurrences of a pattern with another pattern in a given text.
gsub("and", "AND", exampletext, ignore.case=FALSE, fixed=FALSE)## [1] "Grammar is a system of rules which governs the production AND use of utterances in a given language. These rules apply to sound as well as meaning, AND include componential subsets of rules, such as those pertaining to phonology (the organisation of phonetic sound systems), morphology (the formation AND composition of words), AND syntax (the formation AND composition of phrases AND sentences). Many modern theories that deal with the principles of grammar are based on Noam Chomsky's framework of generative linguistics."The function gregexpr informs about if a pattern is present in a text and if so where the pattern begins and how long it is.
gregexpr("and", exampletext, ignore.case=FALSE, perl=FALSE,
fixed=FALSE)## [[1]]
## [1] 59 149 302 329 355 382
## attr(,"match.length")
## [1] 3 3 3 3 3 3
## attr(,"index.type")
## [1] "chars"
## attr(,"useBytes")
## [1] TRUEThe function strsplit splits a text if a pattern occurs. The pattern itself is then no longer present in the result (the . is no longer present in the result).
strsplit(exampletext, "\\. ")## [[1]]
## [1] "Grammar is a system of rules which governs the production and use of utterances in a given language"
## [2] "These rules apply to sound as well as meaning, and include componential subsets of rules, such as those pertaining to phonology (the organisation of phonetic sound systems), morphology (the formation and composition of words), and syntax (the formation and composition of phrases and sentences)"
## [3] "Many modern theories that deal with the principles of grammar are based on Noam Chomsky's framework of generative linguistics."On way to get around this is to first replace the pattern with some sequence that does not occur in the text the gsub function and then splitting on the newly introduced sequence. This way, the original text remains intact.
strsplit(gsub("(\\.) ", "\\1somestring", exampletext), "somestring")## [[1]]
## [1] "Grammar is a system of rules which governs the production and use of utterances in a given language."
## [2] "These rules apply to sound as well as meaning, and include componential subsets of rules, such as those pertaining to phonology (the organisation of phonetic sound systems), morphology (the formation and composition of words), and syntax (the formation and composition of phrases and sentences)."
## [3] "Many modern theories that deal with the principles of grammar are based on Noam Chomsky's framework of generative linguistics."The function paste combines texts and the arguments sep and collapse are there to specify what should occur between the combined texts.
paste(splitexampletext, sep=" ", collapse= " ")## [1] "Grammar is a system of rules which governs the production and use of utterances in a given language. These rules apply to sound as well as meaning, and include componential subsets of rules, such as those pertaining to phonology (the organisation of phonetic sound systems), morphology (the formation and composition of words), and syntax (the formation and composition of phrases and sentences). Many modern theories that deal with the principles of grammar are based on Noam Chomsky's framework of generative linguistics."The function toupper converts text characters to upper case.
toupper(exampletext)## [1] "GRAMMAR IS A SYSTEM OF RULES WHICH GOVERNS THE PRODUCTION AND USE OF UTTERANCES IN A GIVEN LANGUAGE. THESE RULES APPLY TO SOUND AS WELL AS MEANING, AND INCLUDE COMPONENTIAL SUBSETS OF RULES, SUCH AS THOSE PERTAINING TO PHONOLOGY (THE ORGANISATION OF PHONETIC SOUND SYSTEMS), MORPHOLOGY (THE FORMATION AND COMPOSITION OF WORDS), AND SYNTAX (THE FORMATION AND COMPOSITION OF PHRASES AND SENTENCES). MANY MODERN THEORIES THAT DEAL WITH THE PRINCIPLES OF GRAMMAR ARE BASED ON NOAM CHOMSKY'S FRAMEWORK OF GENERATIVE LINGUISTICS."The function tolower converts text characters to lower case.
tolower(exampletext)## [1] "grammar is a system of rules which governs the production and use of utterances in a given language. these rules apply to sound as well as meaning, and include componential subsets of rules, such as those pertaining to phonology (the organisation of phonetic sound systems), morphology (the formation and composition of words), and syntax (the formation and composition of phrases and sentences). many modern theories that deal with the principles of grammar are based on noam chomsky's framework of generative linguistics."The function nchar provides the number of characters of a text.
nchar(exampletext)## [1] 523EXERCISE TIME!
`
- Load the text
linguistics04. How many words does the text consist of?
Answer
readLines("https://slcladal.github.io/data/testcorpus/linguistics04.txt") %>%
paste0(collapse = " ") %>%
strsplit(" ") %>%
unlist() %>%
length() ## [1] 101- How many characters does the text consist of?
Answer
readLines("https://slcladal.github.io/data/testcorpus/linguistics04.txt") %>%
paste0(collapse = " ") %>%
strsplit("") %>%
unlist() %>%
length() ## [1] 673`
These are the most common base functions for string operations is R. We will now turn to string operating functions in the stringr package.
Tidy String Processing
The package stringr is part of the so-called tidyverse - a collection of packages that allows to write R code in a readable manner - and it is the most widely used package for string processing in . The advantage of using stringr is that it makes string processing very easy. All stringr functions share a common structure:
str_function(string, pattern)
The two arguments in the structure of stringr functions are: string which is the character string to be processed and a pattern which is either a simple sequence of characters, a regular expression, or a combination of both. Because the string comes first, the stringr functions are ideal for piping and thus use in tidyverse style R.
All function names of stringr begin with str, then an underscore and then the name of the action to be performed. For example, to replace the first occurrence of a pattern in a string, we should use str_replace(). In the following, we will use stringr functions to perform various operations on the example text. As we have already loaded the tidyverse package, we can start right away with using stringr functions as shown below.
Like nchar in base, str_count provides the number of characters of a text.
str_count(splitexampletext)## [1] 100 295 126The function str_detect informs about whether a pattern is present in a text and outputs a logical vector with TRUE if the pattern occurs and FALSE if it does not.
str_detect(splitexampletext, "and")## [1] TRUE TRUE FALSEThe function str_extract extracts the first occurrence of a pattern, if that pattern is present in a text.
str_extract(exampletext, "and")## [1] "and"The function str_extract_all extracts all occurrences of a pattern, if that pattern is present in a text.
str_extract_all(exampletext, "and")## [[1]]
## [1] "and" "and" "and" "and" "and" "and"The function str_locate provides the start and end position of the match of the pattern in a text.
str_locate(exampletext, "and") ## start end
## [1,] 59 61The function str_locate_all provides the start and end positions of the match of the pattern in a text and displays the result in matrix-form.
str_locate_all(exampletext, "and")## [[1]]
## start end
## [1,] 59 61
## [2,] 149 151
## [3,] 302 304
## [4,] 329 331
## [5,] 355 357
## [6,] 382 384The function str_match extracts the first occurrence of the pattern in a text.
str_match(exampletext, "and") ## [,1]
## [1,] "and"The function str_match_all extracts the all occurrences of the pattern from a text.
str_match_all(exampletext, "and")## [[1]]
## [,1]
## [1,] "and"
## [2,] "and"
## [3,] "and"
## [4,] "and"
## [5,] "and"
## [6,] "and"The function str_remove removes the first occurrence of a pattern in a text.
str_remove(exampletext, "and") ## [1] "Grammar is a system of rules which governs the production use of utterances in a given language. These rules apply to sound as well as meaning, and include componential subsets of rules, such as those pertaining to phonology (the organisation of phonetic sound systems), morphology (the formation and composition of words), and syntax (the formation and composition of phrases and sentences). Many modern theories that deal with the principles of grammar are based on Noam Chomsky's framework of generative linguistics."The function str_remove_all removes all occurrences of a pattern from a text.
str_remove_all(exampletext, "and")## [1] "Grammar is a system of rules which governs the production use of utterances in a given language. These rules apply to sound as well as meaning, include componential subsets of rules, such as those pertaining to phonology (the organisation of phonetic sound systems), morphology (the formation composition of words), syntax (the formation composition of phrases sentences). Many modern theories that deal with the principles of grammar are based on Noam Chomsky's framework of generative linguistics."The function str_replace replaces the first occurrence of a pattern with something else in a text.
str_replace(exampletext, "and", "AND")## [1] "Grammar is a system of rules which governs the production AND use of utterances in a given language. These rules apply to sound as well as meaning, and include componential subsets of rules, such as those pertaining to phonology (the organisation of phonetic sound systems), morphology (the formation and composition of words), and syntax (the formation and composition of phrases and sentences). Many modern theories that deal with the principles of grammar are based on Noam Chomsky's framework of generative linguistics."The function str_replace_all replaces all occurrences of a pattern with something else in a text.
str_replace_all(exampletext, "and", "AND")## [1] "Grammar is a system of rules which governs the production AND use of utterances in a given language. These rules apply to sound as well as meaning, AND include componential subsets of rules, such as those pertaining to phonology (the organisation of phonetic sound systems), morphology (the formation AND composition of words), AND syntax (the formation AND composition of phrases AND sentences). Many modern theories that deal with the principles of grammar are based on Noam Chomsky's framework of generative linguistics."The function str_starts tests whether a given text begins with a certain pattern and outputs a logical vector.
str_starts(exampletext, "and") ## [1] FALSEThe function str_ends tests whether a text ends with a certain pattern and outputs a logical vector.
str_ends(exampletext, "and")## [1] FALSELike strsplit, the function str_split splits a text when a given pattern occurs. If no pattern is provided, then the text is split into individual symbols.
str_split(exampletext, "and") ## [[1]]
## [1] "Grammar is a system of rules which governs the production "
## [2] " use of utterances in a given language. These rules apply to sound as well as meaning, "
## [3] " include componential subsets of rules, such as those pertaining to phonology (the organisation of phonetic sound systems), morphology (the formation "
## [4] " composition of words), "
## [5] " syntax (the formation "
## [6] " composition of phrases "
## [7] " sentences). Many modern theories that deal with the principles of grammar are based on Noam Chomsky's framework of generative linguistics."The function str_split_fixed splits a text when a given pattern occurs but only so often as is indicated by the argument n. So, even if the patter occur more often than n, str_split_fixed will only split the text n times.
str_split_fixed(exampletext, "and", n = 3)## [,1]
## [1,] "Grammar is a system of rules which governs the production "
## [,2]
## [1,] " use of utterances in a given language. These rules apply to sound as well as meaning, "
## [,3]
## [1,] " include componential subsets of rules, such as those pertaining to phonology (the organisation of phonetic sound systems), morphology (the formation and composition of words), and syntax (the formation and composition of phrases and sentences). Many modern theories that deal with the principles of grammar are based on Noam Chomsky's framework of generative linguistics."The function str_subset extracts those subsets of a text that contain a certain pattern.
str_subset(splitexampletext, "and") ## [1] "Grammar is a system of rules which governs the production and use of utterances in a given language."
## [2] "These rules apply to sound as well as meaning, and include componential subsets of rules, such as those pertaining to phonology (the organisation of phonetic sound systems), morphology (the formation and composition of words), and syntax (the formation and composition of phrases and sentences)."The function str_which provides a vector with the indices of the texts that contain a certain pattern.
str_which(splitexampletext, "and")## [1] 1 2The function str_view shows the locations of the first instances of a pattern in a text or vector of texts.
str_view(splitexampletext, "and")The function str_view_all shows the locations of all instances of a pattern in a text or vector of texts.
str_view_all(exampletext, "and")The function str_pad adds white spaces to a text or vector of texts so that they reach a given number of symbols.
# cretae text with white spaces
text <- " this is a text "
str_pad(text, width = 30)## [1] " this is a text "The function str_trim removes white spaces from the beginning(s) and end(s) of a text or vector of texts.
str_trim(text) ## [1] "this is a text"The function str_squish removes white spaces that occur within a text or vector of texts.
str_squish(text)## [1] "this is a text"The function str_wrap removes white spaces from the beginning(s) and end(s) of a text or vector of texts and also those white spaces that occur within a text or vector of texts.
str_wrap(text)## [1] "this is a text"The function str_order provides a vector that represents the order of a vector of texts according to the lengths of texts in that vector.
str_order(splitexampletext)## [1] 1 3 2The function str_sort orders of a vector of texts according to the lengths of texts in that vector.
str_sort(splitexampletext)## [1] "Grammar is a system of rules which governs the production and use of utterances in a given language."
## [2] "Many modern theories that deal with the principles of grammar are based on Noam Chomsky's framework of generative linguistics."
## [3] "These rules apply to sound as well as meaning, and include componential subsets of rules, such as those pertaining to phonology (the organisation of phonetic sound systems), morphology (the formation and composition of words), and syntax (the formation and composition of phrases and sentences)."The function str_to_upper converts all symbols in a text or vector of texts to upper case.
str_to_upper(exampletext) ## [1] "GRAMMAR IS A SYSTEM OF RULES WHICH GOVERNS THE PRODUCTION AND USE OF UTTERANCES IN A GIVEN LANGUAGE. THESE RULES APPLY TO SOUND AS WELL AS MEANING, AND INCLUDE COMPONENTIAL SUBSETS OF RULES, SUCH AS THOSE PERTAINING TO PHONOLOGY (THE ORGANISATION OF PHONETIC SOUND SYSTEMS), MORPHOLOGY (THE FORMATION AND COMPOSITION OF WORDS), AND SYNTAX (THE FORMATION AND COMPOSITION OF PHRASES AND SENTENCES). MANY MODERN THEORIES THAT DEAL WITH THE PRINCIPLES OF GRAMMAR ARE BASED ON NOAM CHOMSKY'S FRAMEWORK OF GENERATIVE LINGUISTICS."The function str_to_lower converts all symbols in a text or vector of texts to lower case.
str_to_lower(exampletext) ## [1] "grammar is a system of rules which governs the production and use of utterances in a given language. these rules apply to sound as well as meaning, and include componential subsets of rules, such as those pertaining to phonology (the organisation of phonetic sound systems), morphology (the formation and composition of words), and syntax (the formation and composition of phrases and sentences). many modern theories that deal with the principles of grammar are based on noam chomsky's framework of generative linguistics."The function str_c combines texts into one text
str_c(exampletext, additionaltext)## [1] "Grammar is a system of rules which governs the production and use of utterances in a given language. These rules apply to sound as well as meaning, and include componential subsets of rules, such as those pertaining to phonology (the organisation of phonetic sound systems), morphology (the formation and composition of words), and syntax (the formation and composition of phrases and sentences). Many modern theories that deal with the principles of grammar are based on Noam Chomsky's framework of generative linguistics.In the early 20th century, Ferdinand de Saussure distinguished between the notions of langue and parole in his formulation of structural linguistics. According to him, parole is the specific utterance of speech, whereas langue refers to an abstract phenomenon that theoretically defines the principles and system of rules that govern a language. This distinction resembles the one made by Noam Chomsky between competence and performance in his theory of transformative or generative grammar. According to Chomsky, competence is an individual's innate capacity and potential for language (like in Saussure's langue), while performance is the specific way in which it is used by individuals, groups, and communities (i.e., parole, in Saussurean terms). "The function str_conv converts a text into a certain type of encoding, e.g. into UTF-8 or Latin1.
str_conv(exampletext, encoding = "UTF-8")## [1] "Grammar is a system of rules which governs the production and use of utterances in a given language. These rules apply to sound as well as meaning, and include componential subsets of rules, such as those pertaining to phonology (the organisation of phonetic sound systems), morphology (the formation and composition of words), and syntax (the formation and composition of phrases and sentences). Many modern theories that deal with the principles of grammar are based on Noam Chomsky's framework of generative linguistics."The function str_dup reduplicates a text or a vector of texts n times.
str_dup(exampletext, times=2)## [1] "Grammar is a system of rules which governs the production and use of utterances in a given language. These rules apply to sound as well as meaning, and include componential subsets of rules, such as those pertaining to phonology (the organisation of phonetic sound systems), morphology (the formation and composition of words), and syntax (the formation and composition of phrases and sentences). Many modern theories that deal with the principles of grammar are based on Noam Chomsky's framework of generative linguistics.Grammar is a system of rules which governs the production and use of utterances in a given language. These rules apply to sound as well as meaning, and include componential subsets of rules, such as those pertaining to phonology (the organisation of phonetic sound systems), morphology (the formation and composition of words), and syntax (the formation and composition of phrases and sentences). Many modern theories that deal with the principles of grammar are based on Noam Chomsky's framework of generative linguistics."The function str_flatten combines a vector of texts into one text. The argument collapse defines the symbol that occurs between the combined texts. If the argument collapse is left out, the texts will be combined without any symbol between the combined texts.
str_flatten(sentences, collapse = " ")## [1] "This is a first sentence. This is a second sentence. And this is a third sentence."If the argument collapse is left out, the texts will be combined without any symbol between the combined texts.
str_flatten(sentences)## [1] "This is a first sentence.This is a second sentence.And this is a third sentence."The function str_length provides the length of texts in characters.
str_length(exampletext)## [1] 523The function str_replace_na replaces NA in texts. It is important to note that NA, if it occurs within a string, is considered to be the literal string NA.
# create sentences with NA
sentencesna <- c("Some text", NA, "Some more text", "Some NA text")
# apply str_replace_na function
str_replace_na(sentencesna, replacement = "Something new")## [1] "Some text" "Something new" "Some more text" "Some NA text"The function str_trunc ends strings with … after a certain number of characters.
str_trunc(sentences, width = 20)## [1] "This is a first s..." "This is a second ..." "And this is a thi..."The function str_sub extracts a string from a text from a start location to an end position (expressed as character positions).
str_sub(exampletext, 5, 25)## [1] "mar is a system of ru"The function word extracts words from a text (expressed as word positions).
word(exampletext, 2:7)## [1] "is" "a" "system" "of" "rules" "which"The function str_glue combines strings and allows to input variables.
name <- "Fred"
age <- 50
anniversary <- as.Date("1991-10-12")
str_glue(
"My name is {name}, ",
"my age next year is {age + 1}, ",
"and my anniversary is {format(anniversary, '%A, %B %d, %Y')}."
)## My name is Fred, my age next year is 51, and my anniversary is Samstag, Oktober 12, 1991.The function str_glue_data is particularly useful when it is used in data pipelines. The data set mtcars is a build in data set that is loaded automatically when starting R.
mtcars %>%
str_glue_data("{rownames(.)} has {hp} hp")## Mazda RX4 has 110 hp
## Mazda RX4 Wag has 110 hp
## Datsun 710 has 93 hp
## Hornet 4 Drive has 110 hp
## Hornet Sportabout has 175 hp
## Valiant has 105 hp
## Duster 360 has 245 hp
## Merc 240D has 62 hp
## Merc 230 has 95 hp
## Merc 280 has 123 hp
## Merc 280C has 123 hp
## Merc 450SE has 180 hp
## Merc 450SL has 180 hp
## Merc 450SLC has 180 hp
## Cadillac Fleetwood has 205 hp
## Lincoln Continental has 215 hp
## Chrysler Imperial has 230 hp
## Fiat 128 has 66 hp
## Honda Civic has 52 hp
## Toyota Corolla has 65 hp
## Toyota Corona has 97 hp
## Dodge Challenger has 150 hp
## AMC Javelin has 150 hp
## Camaro Z28 has 245 hp
## Pontiac Firebird has 175 hp
## Fiat X1-9 has 66 hp
## Porsche 914-2 has 91 hp
## Lotus Europa has 113 hp
## Ford Pantera L has 264 hp
## Ferrari Dino has 175 hp
## Maserati Bora has 335 hp
## Volvo 142E has 109 hpEXERCISE TIME!
`
- Load the text
linguistics04. How many words does the text consist of?
Answer
readLines("https://slcladal.github.io/data/testcorpus/linguistics04.txt") %>%
paste0(collapse = " ") %>%
strsplit(" ") %>%
unlist() %>%
length() ## [1] 101- How many characters does the text consist of?
Answer
readLines("https://slcladal.github.io/data/testcorpus/linguistics04.txt") %>%
paste0(collapse = " ") %>%
strsplit("") %>%
unlist() %>%
length() ## [1] 673`
Citation & Session Info
Schweinberger, Martin. 2021. String processing in R. Brisbane: The University of Queensland. url: https://slcladal.github.io/string.html (Version 2021.10.01).
@manual{schweinberger2021string,
author = {Schweinberger, Martin},
title = {String processing in R},
note = {https://slcladal.github.io/string.html},
year = {2021},
organization = {The University of Queensland, School of Languages and Cultures},
address = {Brisbane},
edition = {2021.10.01}
}sessionInfo()## R version 4.1.1 (2021-08-10)
## Platform: x86_64-w64-mingw32/x64 (64-bit)
## Running under: Windows 10 x64 (build 19043)
##
## Matrix products: default
##
## locale:
## [1] LC_COLLATE=German_Germany.1252 LC_CTYPE=German_Germany.1252
## [3] LC_MONETARY=German_Germany.1252 LC_NUMERIC=C
## [5] LC_TIME=German_Germany.1252
##
## attached base packages:
## [1] stats graphics grDevices utils datasets methods base
##
## other attached packages:
## [1] forcats_0.5.1 stringr_1.4.0 dplyr_1.0.7 purrr_0.3.4
## [5] readr_2.0.1 tidyr_1.1.3 tibble_3.1.4 ggplot2_3.3.5
## [9] tidyverse_1.3.1
##
## loaded via a namespace (and not attached):
## [1] tidyselect_1.1.1 xfun_0.26 haven_2.4.3 colorspace_2.0-2
## [5] vctrs_0.3.8 generics_0.1.0 htmltools_0.5.2 yaml_2.2.1
## [9] utf8_1.2.2 rlang_0.4.11 pillar_1.6.2 glue_1.4.2
## [13] withr_2.4.2 DBI_1.1.1 dbplyr_2.1.1 modelr_0.1.8
## [17] readxl_1.3.1 lifecycle_1.0.0 munsell_0.5.0 gtable_0.3.0
## [21] cellranger_1.1.0 rvest_1.0.1 htmlwidgets_1.5.4 evaluate_0.14
## [25] knitr_1.34 tzdb_0.1.2 fastmap_1.1.0 fansi_0.5.0
## [29] highr_0.9 broom_0.7.9 Rcpp_1.0.7 scales_1.1.1
## [33] backports_1.2.1 jsonlite_1.7.2 fs_1.5.0 hms_1.1.0
## [37] digest_0.6.27 stringi_1.7.4 grid_4.1.1 cli_3.0.1
## [41] tools_4.1.1 magrittr_2.0.1 klippy_0.0.0.9500 crayon_1.4.1
## [45] pkgconfig_2.0.3 ellipsis_0.3.2 xml2_1.3.2 reprex_2.0.1.9000
## [49] lubridate_1.7.10 rstudioapi_0.13 assertthat_0.2.1 rmarkdown_2.5
## [53] httr_1.4.2 R6_2.5.1 compiler_4.1.1