scan_re: Scan a regular expression, or any other character string,...
In wai-wong-reimagine/mclm: Mastering Corpus Linguistics Methods

Description Usage Details Value See Also

The functions scan_re and scan_txt, which take no arguments, can be used to scan a text string from the console. After the function call, R will continue scanning your input until it encounters an empty input line, i.e. until it encounters two consecutive newline symbols (or until it encounters a line with nothing but whitespace characters). In other words, press ENTER twice in a row if you want to stop inputting characters. The function will then return your input as a character vector of length one.

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scan_re()

scan_txt()

Both functions, scan_re and scan_txt, behave in exactly the same way. The first name, scan_re, emphasizes that the functions are specifically meant for inputting regular expressions. The second name, scan_txt, emphasizes that you can nevertheless also use the functions for scanning any other string.

The specific reason why the functions are created, is to avoid the need for doubling backslashes when inputting regular expressions. When regular expressions are in a string literal, the special meaning of backslashes in R string literals forces one to double these backslashes, which is especially inconvenient because backslashes feature prominently in regular expression notation. The functions functions scan_re and scan_txt interpret their input as ‘raw strings’. Therefore, there is no need for doubling backslashes.

Returns a character vector of length one that contains the string that has been scanned.

See also cat_re.

wai-wong-reimagine/mclm documentation built on May 16, 2019, 9:12 p.m.