Character Manipulation and Data Processing

name <- c("Moe Szyslak", "Burns, C. Montgomery", "Rev. Timothy Lovejoy",
          "Ned Flanders", "Simpson, Homer", "Dr. Julius Hibbert")

# 3. Rearrange the vector so that all elements conform to the standard
# first_name last_name

# split the vector based on spaces
name_split <- strsplit(name, " ")
name_split

## [[1]]
## [1] "Moe"     "Szyslak"
## 
## [[2]]
## [1] "Burns,"     "C."         "Montgomery"
## 
## [[3]]
## [1] "Rev."    "Timothy" "Lovejoy"
## 
## [[4]]
## [1] "Ned"      "Flanders"
## 
## [[5]]
## [1] "Simpson," "Homer"   
## 
## [[6]]
## [1] "Dr."     "Julius"  "Hibbert"

check_name_prefix <- function(nameString)
{
   regexpr("\\.", nameString[1])
}

sapply(name, check_name_prefix)

##          Moe Szyslak Burns, C. Montgomery Rev. Timothy Lovejoy 
##                   -1                    9                    4 
##         Ned Flanders       Simpson, Homer   Dr. Julius Hibbert 
##                   -1                   -1                    3

1. The regexular expression “[0-9]+\$” matches any string that ends with

one or more digits followed by a  character

2. The regular expression “\b[a-z]{1,4}\b” matches any string that starts

with a followed by 1-4 characters of the alphabet followed by a

3. The regular expression “.*?\.txt$" matches any string that ends with a

.txt at the end

4. The regular expression “\d{2}/\d{2}/\d{4}” matches only the following

string

5. The regular expression “”<(.+?)>.+?</\1>" matches a string starting with

one or more characters enclosed in angular brackets then followed by one or

more characters followed by <> at the end.

prob4.1 <- "[0-9]+\\$"

example_prob4.1 <- regexpr(prob4.1, "mypassword2016\\")
example_prob4.1

## [1] -1
## attr(,"match.length")
## [1] -1
## attr(,"useBytes")
## [1] TRUE

prob4.2 <- "\\b[a-z]{1,4}\\b"
# Examples:
# "\bobby\b"
# "\bush\b"
# "\boy\b"

example_prob4.2 <- regexpr(prob4.2, "\bobby\b")
example_prob4.2

## [1] 2
## attr(,"match.length")
## [1] 4
## attr(,"useBytes")
## [1] TRUE

prob4.3 <- ".*?\\.txt$"
# Examples:
# "CUNYSPS\.txt"
# "nc9aqt\.txt"

example_prob4.3 <- regexpr(prob4.3, "mnvac4534\\.txt")
example_prob4.3

## [1] 1
## attr(,"match.length")
## [1] 14
## attr(,"useBytes")
## [1] TRUE

prob4.4 <- "\\d{2}/\\d{2}\\d{4}"
example_prob4.4 <- regexpr(prob4.4, "\\dd\\dd\\dddd")
example_prob4.4

## [1] -1
## attr(,"match.length")
## [1] -1
## attr(,"useBytes")
## [1] TRUE

prob4.5 <- "<(.+?)>.+?</\\1>"
example_prob4.5 <- regexpr(prob4.5, "<nfoaetyey49y5>j437n9m8byt<\1>")
example_prob4.5

## [1] -1
## attr(,"match.length")
## [1] -1
## attr(,"useBytes")
## [1] TRUE