library(dplyr)

## Warning: package 'dplyr' was built under R version 4.3.3

## 
## Attaching package: 'dplyr'

## The following objects are masked from 'package:stats':
## 
##     filter, lag

## The following objects are masked from 'package:base':
## 
##     intersect, setdiff, setequal, union

data <- "https://raw.githubusercontent.com/fivethirtyeight/data/master/college-majors/majors-list.csv"
majors <- read.csv(data, stringsAsFactors = FALSE)

filtered_majors <- majors %>%
  filter(grepl("DATA|STATISTICS", Major, ignore.case = TRUE))

filtered_majors

##   FOD1P                                         Major          Major_Category
## 1  6212 MANAGEMENT INFORMATION SYSTEMS AND STATISTICS                Business
## 2  2101      COMPUTER PROGRAMMING AND DATA PROCESSING Computers & Mathematics
## 3  3702               STATISTICS AND DECISION SCIENCE Computers & Mathematics

fruits_vegetables <- c("bell pepper", "bilberry", "blackberry", "blood orange", "blueberry", "cantaloupe", "chili pepper", "cloudberry", "elderberry", "lime", "lychee", "mulberry", "olive", "salal berry")

cat(paste0("c(", paste(shQuote(fruits_vegetables, type = "cmd"), collapse = ", "), ")"))

## c("bell pepper", "bilberry", "blackberry", "blood orange", "blueberry", "cantaloupe", "chili pepper", "cloudberry", "elderberry", "lime", "lychee", "mulberry", "olive", "salal berry")

(.)\1\1 This expression matches any character that is repeated three times.

“(.)(.)\2\1” This expression matches if two characters are repeated backwards after the first two. A four letter or symbol palindrome. Example: xyyx

(..)\1 This expression matches if two characters are repeated identically.

“(.).\1.\1” This expression matches the placement of the first character if it appears third and fifth in a string.

“(.)(.)(.).*\3\2\1” This expression matches if three characters are found in reverse order at the end of a string. The characters and the number of characters inbetween do not matter if the last three are the same as the first three reversed.

words <- c("radar", "level", "hello", "world", "a", "racecar")
pattern <- "^(.).*\\1$"
matches <- grepl(pattern, words)
words[matches]

## [1] "radar"   "level"   "racecar"

words1 <- c("salsa", "mama", "world", "hello", "banana")
pattern_w <- "(..).*\\1"
matches1 <- grepl(pattern_w, words1)
words1 [matches1]

## [1] "salsa" "mama"

words2 <- c("seventy", "ethereal", "surprises", "other", "masks")
pattern2 <- "(.).*\\1.*\\1"
matches2 <- grepl(pattern2, words2)
words2 [matches2]

## [1] "ethereal"  "surprises"

words3 <- c("abcdeffedcba", "000abc000abc", "000abc000", "dada")
pattern3 <- "(.)(.)(.).*\\3\\2\\1"
matches3 <- grepl(pattern3, words3)
words3[matches3]

## [1] "abcdeffedcba" "000abc000abc" "000abc000"