Assignment 3

Homework Questions

3. Copy the introductory example. The vector name stores the extracted names. R> name [1] “Moe Szyslak” “Burns, C. Montgomery” “Rev. Timothy Lovejoy” [4] “Ned Flanders” “Simpson, Homer” “Dr. Julius Hibbert”

library(stringr)
raw.data <- "555-1239Moe Szyslak(636) 555-0113Burns, C. Montgomery555-6542Rev. Timothy Lovejoy555 8904Ned Flanders636-555-3226Simpson, Homer5543642Dr. Julius Hibbert"
raw.data

## [1] "555-1239Moe Szyslak(636) 555-0113Burns, C. Montgomery555-6542Rev. Timothy Lovejoy555 8904Ned Flanders636-555-3226Simpson, Homer5543642Dr. Julius Hibbert"

1. Use the tools of this chapter to rearrange the vector so that all elements conform to the standard first_name last_name.

name <- unlist(str_extract_all(raw.data, "[[:alpha:]., ]{2,}"))
name

## [1] "Moe Szyslak"          "Burns, C. Montgomery" "Rev. Timothy Lovejoy"
## [4] "Ned Flanders"         "Simpson, Homer"       "Dr. Julius Hibbert"

name_remove_title_middle <- str_replace(name, "([[:alpha:]]{1,3}\\.\\s)", "")
name_first_last <- str_replace(name_remove_title_middle, "([[:alpha:]]+), ([[:alpha:]]+)", "\\2 \\1")
name_first_last

## [1] "Moe Szyslak"      "Montgomery Burns" "Timothy Lovejoy" 
## [4] "Ned Flanders"     "Homer Simpson"    "Julius Hibbert"

2. Construct a logical vector indicating whether a character has a title (i.e., Rev. and Dr.).

str_detect(name, "Dr.|Rev.")

## [1] FALSE FALSE  TRUE FALSE FALSE  TRUE

3. Construct a logical vector indicating whether a character has a second name.

str_count(str_trim(str_replace_all(name, "Dr.|Rev.", "")), " ") > 1

## [1] FALSE  TRUE FALSE FALSE FALSE FALSE

4. Describe the types of strings that conform to the following regular expressions and construct an example that is matched by the regular expression.

1. [0-9]+\$

t<-c("test$", "$24$03", 2403)
unlist(str_extract_all(t, "[0-9]+\\$"))

## [1] "24$"

2. \b[a-z]{1,4}\b

st<-"This is a test of question 4b"
unlist(str_extract_all(st, "\\b[a-z]{1,4}\\b"))

## [1] "is"   "a"    "test" "of"

3. .*?\.txt$

tt<-c("test.txt","test.xlsx","test.docx")
unlist(str_extract_all(tt, ".*?\\.txt$"))

## [1] "test.txt"

4. \d{2}/\d{2}/\d{4}

ft<- c("2/12/19","02/12/2019","02/12/19")
unlist(str_extract_all(ft,"\\d{2}/\\d{2}/\\d{4}"))

## [1] "02/12/2019"

5. <(.+?)>.+?</\1>

fit<-c("<test>blah</test>","<\test>","<tester>")
unlist(str_extract_all(fit,"<(.+?)>.+?</\\1>"))

## [1] "<test>blah</test>"

Extra Credit

9. The following code hides a secret message. Crack it with R and regular expressions. Hint: Some of the characters are more revealing than others! The code snippet is also available in the materials at www.r-datacollection.com. clcopCow1zmstc0d87wnkig7OvdicpNuggvhryn92Gjuwczi8hqrfpRxs5Aj5dwpn0Tanwo Uwisdij7Lj8kpf03AT5Idr3coc0bt7yczjatOaootj55t3Nj3ne6c4Sfek.r1w1YwwojigO d6vrfUrbz2.2bkAnbhzgv4R9i05zEcrop.wAgnb.SqoU65fPa1otfb7wEm24k6t3sR9zqe5 fy89n6Nd5t9kc4fE905gmc4Rgxo5nhDk!gr

sc<- "c1copCow1zmstc0d87wnkig7OvdicpNuggvhryn92Gjuwczi8hqrfpRxs5Aj5dwpn0TanwoUwisdij7Lj8kpf0w3AT5Idr3coc0bt7yczjatOaootj55t3Nj3ne6c4Sfek.r1w1YwwojigOd6vrfUrbz2.2bkAnbhzgv4R9i05zEcrop.wAgnb.SqoU65fPalotfb7wEm24k6t3sR9zqe5fy89n6Nd5t9kc4fE905gmc4Rgxo5nhDk!gr"
extractsc <- unlist(str_extract_all(sc, "[[:upper:]]|[[:punct:]]"))
combinesc <- paste(extractsc, collapse = '')
secretmessage<-str_replace_all(combinesc, "\\.", " ")
secretmessage

## [1] "CONGRATULATIONS YOU ARE A SUPERNERD!"