Week 3 Assignment

Elina Azrilyan

Data 607

09/13/2018

Problem 3. Copy the introductory example. The vector name stores the extracted names.

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

#install.packages("stringr", repos='http://cran.us.r-project.org')
library("stringr")
raw.data <- "555-1239Moe Szyslak(636) 555-0113Burns, C. Montgomery555-6542Rev.Timothy Lovejoy555 8904Ned Flanders636-555-3226Simpson, Homer5553642Dr.Julius Hibbert"
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"

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

# This code removes all titles and middle initials
name2 <- str_replace(name, "\\s*\\w{1,3}[.]",  "")
name2

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

# This code reorders first and last names if they were in the wrong format. 
#I started with the code found on the following help page: https://stackoverflow.com/questions/33826650/last-name-first-name-to-first-name-last-name
str_replace(name2, "(\\w+),\\s(\\w+)","\\2 \\1")

## [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.).

name

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

str_detect(name, "\\s*\\w{2,3}[.]")

## [1] FALSE FALSE  TRUE FALSE FALSE  TRUE

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

name

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

str_detect(name, "\\s{1}\\w{1}[.]")

## [1] FALSE  TRUE FALSE FALSE FALSE FALSE

Problem 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: It is 1 or more numbers followed by a “$”.

Examples are:

test<-"jfdlsae43543fjdk$slfjsdk2354325$jfdksaf45$"
unlist(str_extract_all(test, "[0-9]+\\$"))

## [1] "2354325$" "45$"

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

Answer: It will return all lower case words between 1 and 4 letters.

Examples are:

test<-"What a lovely day it is, there is not even a rain drop. 43543rere 235"
unlist(str_extract_all(test, "\\b[a-z]{1,4}\\b"))

##  [1] "a"    "day"  "it"   "is"   "is"   "not"  "even" "a"    "rain" "drop"

3. .*?\.txt$

Answer: It will return experession of any length and any characters as long as it includes “.txt”" in the end.

Example is:

test<-"af45$ 4832$fjdsl something.txt gfdsgf54665$%&&ggfdsf.txt"
unlist(str_extract_all(test, ".*?\\.txt$"))

## [1] "af45$ 4832$fjdsl something.txt gfdsgf54665$%&&ggfdsf.txt"

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

Answer: This expression will return 2digits/2digits/4digits - similar to a date format.

Example is:

test<-"af45$ 4832$fjdsl something.txt 06/30/1984 sfjdskaj 34666 44"
unlist(str_extract_all(test, "\\d{2}/\\d{2}/\\d{4}"))

## [1] "06/30/1984"

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

Answer: This will return any character or multiple characters surrounded by < > followed by another character or any number of characters and then followed by </ and initial character.

Example:

test<- "fdsjkflsdaj <(sfssfdsfs)>   <tada>ffffaaaa</tada>"
unlist(str_extract_all(test, "<(.+?)>.+?</\\1>"))

## [1] "<tada>ffffaaaa</tada>"

Problem 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.

 lcopCow1zmstc0d87wnkig7OvdicpNuggvhryn92Gjuwczi8hqrfpRxs5Aj5dwpn0Tanwo
 Uwisdij7Lj8kpf03AT5Idr3coc0bt7yczjatOaootj55t3Nj3ne6c4Sfek.r1w1YwwojigO
 d6vrfUrbz2.2bkAnbhzgv4R9i05zEcrop.wAgnb.SqoU65fPa1otfb7wEm24k6t3sR9zqe5
 fy89n6Nd5t9kc4fE905gmc4Rgxo5nhDk!gr
 

coded.message <- "clcopCow1zmstc0d87wnkig7OvdicpNuggvhryn92Gjuwczi8hqrfpRxs5Aj5dwpn0TanwoUwisdij7Lj8kpf03AT5Idr3coc0bt7yczjatOaootj55t3Nj3ne6c4Sfek.r1w1YwwojigOd6vrfUrbz2.2bkAnbhzgv4R9i05zEcrop.wAgnb.SqoU65fPa1otfb7wEm24k6t3sR9zqe5fy89n6Nd5t9kc4fE905gmc4Rgxo5nhDk!gr"
unlist(str_extract_all(coded.message, "[[:punct:]A-Z]"))

##  [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" "!"

Yes… Yes, I am:)