Data 607 Week 3 Assignment

Copy the introductory example. The vector name stores the extracted names.

library(stringr)

raw.data<-"555-1239Moe Szyslak(636) 555-0113Burns, C. Montgomery555-6542Rev. Timothy Lovejoy555 8904Ned Flanders636-555-3226Simpson, Homer5553642Dr. Julius Hibbert"
raw.data

## [1] "555-1239Moe Szyslak(636) 555-0113Burns, C. Montgomery555-6542Rev. Timothy Lovejoy555 8904Ned Flanders636-555-3226Simpson, Homer5553642Dr. 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"

# Remove the title
name <- str_replace(name,"[[:alpha:]]{2,}\\. ", "")
name

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

# Extract the first name
first_name <- str_extract(name, "^[[:alpha:]]+\\.?")
last_name <- str_extract(name, "[[:alpha:]]+$")
# Trim whitespace
first_name <- str_trim(first_name)
last_name <- str_trim(last_name)
first_last <-  str_c(first_name, last_name, sep = " ")
first_last

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

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

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]+\$ Answer: Match any number 0 to 9 one or more times followed by a $ charcter at the end.

str <- "I've 1500$ for my monthly expenses."
str_extract(str,"[0-9]+\\$")

## [1] "1500$"

2. \b[a-z]{1,4}\b Answer: Matches any 1 to 4 charcter lowercase letter a to z in a whole word search.

str <- "Any character one to four digit lowercase letter.No digits 123etc are allowed."
str_extract(str,"\\b[a-z]{1,4}\\b")

## [1] "one"

3. .*?\.txt$ Answer: This regular expression matches any character followed by “.txt” at then end.

str <- c(".txt","file.txt","big_data.txt","I'm a word")
unlist(str_extract_all(str,".*?\\.txt$"))

## [1] ".txt"         "file.txt"     "big_data.txt"

4. \d{2}/\d{2}/\d{4} Answer: This regular expression matches dates where the first and second part is 2 digit number and the last part is a 4 digit number.

str_extract("02/16/2019","\\d{2}/\\d{2}/\\d{4}")

## [1] "02/16/2019"

5. <(.+?)>.+?</\1> Answer: This expressoin matches any html opening and closing tags.

str_extract("<title>This is a title</title>","<(.+?)>.+?</\\1>")

## [1] "<title>This is a title</title>"

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.

str <- "clcopCow1zmstc0d87wnkig7OvdicpNuggvhryn92Gjuwczi8hqrfpRxs5Aj5dwpn0Tanwo
Uwisdij7Lj8kpf03AT5Idr3coc0bt7yczjatOaootj55t3Nj3ne6c4Sfek.r1w1YwwojigO
d6vrfUrbz2.2bkAnbhzgv4R9i05zEcrop.wAgnb.SqoU65fPa1otfb7wEm24k6t3sR9zqe5
fy89n6Nd5t9kc4fE905gmc4Rgxo5nhDk!gr"

# Extract all the upper case
message <- unlist(str_extract_all(str,"[[:upper:].! ]"))
message

##  [1] "C" "O" "N" "G" "R" "A" "T" "U" "L" "A" "T" "I" "O" "N" "S" "." "Y"
## [18] "O" "U" "." "A" "R" "E" "." "A" "." "S" "U" "P" "E" "R" "N" "E" "R"
## [35] "D" "!"

# Make a sentence by joining
message <- paste(message, collapse = "")
message

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

# Replace . by space
message <- str_replace_all(message,"\\."," ")
message

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