Assignment Homework-3-607: Character manipulation and expressions

Summary of Assignment This assignment involves character manipulation and expressions using R.

This Assignment requires the following:

1). R-Studio

The following R-packages are used: 1.stringr

Steps to reproduce: 1). run the R-Studio file: R_607_Week_3b_Hmk_Char_Manipulation_Daniel_Thonn.Rmd

Setting up and Preparing the Environment

#install.packages("stringr")
library(stringr)

Load the character names data into an R dataframe

name <- c("Moe Szyslak","Burns, C. Montgomery","Rev. Timothy Lovejoy","Ned Flanders", "Simpson, Homer","Dr. Julius Hibbert")
list(name)
## [[1]]
## [1] "Moe Szyslak"          "Burns, C. Montgomery" "Rev. Timothy Lovejoy"
## [4] "Ned Flanders"         "Simpson, Homer"       "Dr. Julius Hibbert"
  1. 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”
  1. Use the tools of this chapter to rearrange the vector so that all elements conform to the standard first_name last_name.
  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.
#3a).

# use str_split: Split the elements of a character vector x into substrings according to the matches to substring split within them. 

# use sapply: traverse over a set of data like a list or vector, and calling the specified function for each item.

name2 = sapply(strsplit(name, split=", "),function(y) 
  {paste(rev(y),collapse=" ")})

list(name2)
## [[1]]
## [1] "Moe Szyslak"          "C. Montgomery Burns"  "Rev. Timothy Lovejoy"
## [4] "Ned Flanders"         "Homer Simpson"        "Dr. Julius Hibbert"
#3b). Check Titles

#str_detect: .  str_detect() detects the presence or absence of a pattern and returns a logical vector 

has_title <- data.frame (name2, str_detect(name2,"Rev.|Dr."))
list (has_title)
## [[1]]
##                  name2 str_detect.name2...Rev..Dr...
## 1          Moe Szyslak                         FALSE
## 2  C. Montgomery Burns                         FALSE
## 3 Rev. Timothy Lovejoy                          TRUE
## 4         Ned Flanders                         FALSE
## 5        Homer Simpson                         FALSE
## 6   Dr. Julius Hibbert                          TRUE
#3c). Check Second Names

second_name <- data.frame(name, str_detect(name," [A-Z]\\."))
list (second_name)
## [[1]]
##                   name str_detect.name.....A.Z......
## 1          Moe Szyslak                         FALSE
## 2 Burns, C. Montgomery                          TRUE
## 3 Rev. Timothy Lovejoy                         FALSE
## 4         Ned Flanders                         FALSE
## 5       Simpson, Homer                         FALSE
## 6   Dr. Julius Hibbert                         FALSE
  1. 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]+\$
  2. \b[a-z]{1,4}\b
  3. .*?\.txt$
  4. \d{2}/\d{2}/\d{4}
  5. <(.+?)>.+?</\1>
#4a).[0-9]+\\$ : contains one or more numbers then a $ sign

Four_a <- "111$"
str_detect(Four_a,"[0-9]+\\$")
## [1] TRUE
#4b).\\b[a-z]{1,4}\\b: A word with one to four letters  

Four_b <- c("t","test","test1","testtt")
str_detect(Four_b,"\\b[a-z]{1,4}\\b")
## [1]  TRUE  TRUE FALSE FALSE
#4c). .*?\\.txt$: A word with period and ending in .txt
Four_c <- c("test.txt","test","t.text","testtt.txt","txttxt")
str_detect(Four_c,".*?\\.txt$")
## [1]  TRUE FALSE FALSE  TRUE FALSE
#4d). \\d{2}/\\d{2}/\\d{4} : character patterns with 2 digits, forward slash, 2 digits, forward slash, 4 digits

Four_d <- c("11/11/1111","1/11/1111","11/1/1111","11/11/111")
str_detect(Four_d,"\\d{2}/\\d{2}/\\d{4}")
## [1]  TRUE FALSE FALSE FALSE
  1. 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

string1 <- "clcopCow1zmstc0d87wnkig7OvdicpNuggvhryn92Gjuwczi8hqrfpRxs5Aj5dwpn0Tanwo
Uwisdij7Lj8kpf03AT5Idr3coc0bt7yczjatOaootj55t3Nj3ne6c4Sfek.r1w1YwwojigO
d6vrfUrbz2.2bkAnbhzgv4R9i05zEcrop.wAgnb.SqoU65fPa1otfb7wEm24k6t3sR9zqe5
fy89n6Nd5t9kc4fE905gmc4Rgxo5nhDk!gr"

string2 <-unlist(str_extract_all(string1,"[[:upper:].]{1,}"))
string2
##  [1] "C"  "O"  "N"  "G"  "R"  "A"  "T"  "U"  "L"  "AT" "I"  "O"  "N"  "S" 
## [15] "."  "Y"  "O"  "U"  "."  "A"  "R"  "E"  "."  "A"  ".S" "U"  "P"  "E" 
## [29] "R"  "N"  "E"  "R"  "D"
string3 <- str_replace_all(paste(string2, collapse = ''), "[.]", " ")
string3
## [1] "CONGRATULATIONS YOU ARE A SUPERNERD"

END