regex_supplement: Supplemental Canned Regular Expressions

In qdapRegex: Regular Expression Removal, Extraction, and Replacement Tools

Supplemental Canned Regular Expressions

Description

A dataset containing a list of supplemental, canned regular expressions. The regular expressions in this data set are considered useful but have not been included in a formal function (of the type rm_XXX). Users can utilize the rm_ function to generate functions that can sub/replace/extract as desired.

Usage

data(regex_supplement)

Format

A list with 24 elements

Details

The following canned regular expressions are included:

after_a

single word after the word "a"

after_the

single word after the word "the"

after_

find single word after ? word (? = user defined); note contains "%s" that is replaced by sprintf and is not a valid regex on its own (user supplies (1) n before, (2) the point, & (3) n after)

around_

find n words (not including punctuation) before or after ? word (? = user defined); note contains "%s" that is replaced by sprintf and is not a valid regex on its own (user supplies (1) n before, (2) the point, & (3) n after)

around2_

find n words (plus punctuation) before or after ? word (? = user defined); note contains "%s" that is replaced by sprintf and is not a valid regex on its own

before_

find sing word before ? word (? = user defined); note contains "%s" that is replaced by sprintf and is not a valid regex on its own

except_first

find all occurrences of a substring except the first; regex pattern retrieved from StackOverflow's akrun: https://stackoverflow.com/a/31458261/1000343

hexadecimal

substring beginning with hash (#) followed by either 3 or 6 select characters (a-f, A-F, and 0-9)

ip_address

substring of four chunks of 1-3 consecutive digits separated with dots (.)

last_occurrence

last occurrence of a delimiter; note contains "%s" that is replaced by sprintf and is not a valid regex on its own (user supplies the delimiter)

pages

substring with "pp." or "p.", optionally followed by a space, followed by 1 or more digits, optionally followed by a dash, optionally followed by 1 or more digits, optionally followed by a semicolon, optionally followed by a space, optionally followed by 1 or more digits; intended for extraction/removal purposes

pages2

substring 1 or more digits, optionally followed by a dash, optionally followed by 1 or more digits, optionally followed by a semicolon, optionally followed by a space, optionally followed by 1 or more digits; intended for validation purposes

punctuation

punctuation characters ([:punct:]) with the ability to negate; note contains "%s" that is replaced by sprintf and is not a valid regex on its own

run_split

a regex that is useful for splitting strings in the characters runs (e.g., "wwxyyyzz" becomes "ww", "x", "yyy", "zz"); regex pattern retrieved from Robert Redd: https://stackoverflow.com/a/29383435/1000343

split_keep_delim

regex string that splits on a delimiter and retains the delimiter

thousands_separator

chunks digits > 4 into groups of 3 from right to left allowing for easy insertion of thousands separator; regex pattern retrieved from StackOverflow's stema: https://stackoverflow.com/a/10612685/1000343

time_12_hours

substring of valid hours (1-12) followed by a colon (:) followed by valid minutes (0-60), followed by an optional space and the character chunk am or pm

version

substring starting with "v" or "version" optionally followed by a space and then period separated digits for <major>.<minor>.<release>.<build>; the build sequence is optional and the "version"/"v" IS NOT contained in the substring

version2

substring starting with "v" or "version" optionally followed by a space and then period separated digits for <major>.<minor>.<release>.<build>; the build sequence is optional and the "version"/"v" IS contained in the substring

white_after_comma

substring of white space after a comma

word_boundary

A true word boundary that only includes alphabetic characters; based on https://www.rexegg.com/'s suggestion taken from discussion of true word boundaries; note contains "%s" that is replaced by sprintf and is not a valid regex on its own

word_boundary_left

A true left word boundary that only includes alphabetic characters; based on https://www.rexegg.com/'s suggestion taken from discussion of true word boundaries

word_boundary_right

A true right word boundary that only includes alphabetic characters; based on https://www.rexegg.com/'s suggestion taken from discussion of true word boundaries

youtube_id

substring of the video id from a YouTube video; taken from Jacob Overgaard's submission found https://regex101.com/r/kU7bP8/1

Regexes from this data set can be added to the pattern argument of any rm_XXX function via an at sign (@) followed by a regex name from this data set (e.g., pattern = "@after_the") provided the regular expression does not contain non-regex such as sprintf character string %s.

Use qdapRegex:::examine_regex(regex_supplement) to interactively explore the regular expressions in regex_usa. This will provide a browser + console based break down of each regex in the dictionary.

Warning

Note that regexes containing %s are replaced by sprintf and are not a valid regex on their own. The S is useful for adding these missing %s parameters.

Examples

time <- rm_(pattern="@time_12_hours")
time("I will go at 12:35 pm")

x <- "v6.0.156 for Windows 2000/2003/XP/Vista
Server version 1.1.20
Client Manager version 1.1.24"

rm_default(x, pattern = "@version", extract=TRUE)
rm_default(x, pattern = "@version2", extract=TRUE)

x <- "this is 1000000 big 4356.  And little 123 number."
rm_default(x, pattern="@thousands_separator", replacement="\\1,")
rm_default(x, pattern="@thousands_separator", replacement="\\1.")

rm_default("I was,but it costs 10,000.", pattern="@white_after_comma", 
    replacement=", ")

x <- "I like; the donuts; a lot"
strsplit(x, ";")
strsplit(x, S(grab("split_keep_delim"), ";"), perl=TRUE)
stringi::stri_split_regex(x, S(grab("split_keep_delim"), ";"))
stringi::stri_split_regex("I like; the donuts; a lot:cool", 
    S(grab("split_keep_delim"), ";|:"))

## Grab words around a point
x <- c(
    "the magic word is e",
    "the dog is red and they are blue",
    "I am new but she is not new",
    "hello world",
    "why is it so cold?  Perhaps it is Winter.",
    "It is not true the 7 is 8.",
    "Is that my drink?"
)

rm_default(x, pattern = S("@around_", 1, "is", 1), extract=TRUE)
rm_default(x, pattern = S("@around_", 2, "is", 2), extract=TRUE)
rm_default(x, pattern = S("@around_", 1, "is|are|am", 1), extract=TRUE)
rm_default(x, pattern = S("@around_", 1, "is not|is|are|am", 1), extract=TRUE)
rm_default(x, pattern = S("@around_", 1, 
    "is not|[Ii]s|[Aa]re|[Aa]m", 1), extract=TRUE)

x <- c(
    "hello world",
    "45",
    "45 & 5 makes 50",
    "x and y",
    "abc and def",
    "her him foo & bar for Jack and Jill then"
)

around_and <- rm_(pattern = S("@around_", 1, "and|\\&", 1), extract=TRUE)
around_and(x)

## Split runs into chunks
x <- "1111100000222000333300011110000111000"
strsplit(x, grab("@run_split"), per = TRUE)

## Not run: 
library(qdap);library(ggplot2);library(reshape2)

out <- setNames(lapply(c("@after_a", "@after_the"), function(x) {
    o <- rm_default(stringi:::stri_trans_tolower(pres_debates2012$dialogue), 
        pattern = x, extract=TRUE)
    m <- qdapTools::matrix2df(data.frame(freq=sort(table(unlist(o)), TRUE)), "word")
    m[m$freq> 7, ]
}), c("a", "the"))


dat <- setNames(Reduce(function(x, y) {
    merge(x, y, by = "word", all = TRUE)}, out), c("Word", "A", "THE"))

dat <- reshape2::melt(dat, id="Word", variable.name="Article", value.name="freq")

dat <- dat[order(dat$freq, dat$Word), ]

ord <- aggregate(freq ~ Word, dat, sum)

dat$word <- factor(dat$Word, levels=ord[order(ord[[2]]), 1])
ggplot(dat, aes(x=freq, y=Word)) + geom_point()+ facet_grid(~Article)

## End(Not run)

## remove/extract pages numbers
x <- c("I read p. 36 and then pp. 45-49", "it's on pp. 23-24;28")

rm_pages <- rm_(pattern="@pages", extract=TRUE)
rm_pages(x)

rm_default(x, pattern = "@pages")
rm_default(x, pattern = "@pages", extract=TRUE)
rm_default(x, pattern = "@pages2", extract=TRUE)

## Validate pages
page_val <- validate("@pages2", FALSE)
page_val(c(66, "78-82", "hello world", TRUE, "44-45; 56"))

## Split on last occurrence
x <- c(
    "test@[e-mail]", 
    "[e-mail]", 
    "test@xyz@[e-mail]", 
    "[e-mail]@zz.vv.net"
)

strsplit(x, S("@last_occurrence", "\\."), perl=TRUE)
strsplit(x, S("@last_occurrence", "@"), perl=TRUE)

## True Word Boundaries
x <- "this is _not a word666 and this is not a word too." 
## Standard regex word boundary
rm_default(x, pattern=bind("not a word"))
## Alphabetic only word boundaries
rm_default(x, pattern=S("@word_boundary", "not a word"))

## Remove all but first occurrence of something
x <- c(
    "12-3=4-5=678-9", 
    "ABC-D=EF2-GHI-JK3=L-MN=", 
    "9-87=65", 
    "a - de=4fgh --= i5jkl", 
    NA
)

rm_default(x, pattern = S("@except_first", "-"))
rm_default(x, pattern = S("@except_first", "="))

qdapRegex documentation built on Oct. 17, 2023, 5:06 p.m.