Libraries used:

library(knitr)
## Warning: package 'knitr' was built under R version 3.5.3
library(ggplot2)
## Warning: package 'ggplot2' was built under R version 3.5.3
library(png)
library(stringr)
## Warning: package 'stringr' was built under R version 3.5.3

Problem 3

imgage <- "C:/Users/jpsim/Documents/DATA Acquisition and Management/3.3.png"
include_graphics(imgage)

Data Setup

# data input
rdata <- "555-1239Moe Szyslak(636) 555-0113Burns, C. Montgomery555-6542Rev. Timothy Lovejoy555 8904Ned Flanders636-555-3226Simpson, Homer5553642Dr. Julius Hibbert"
names <- unlist(str_extract_all(rdata, "[[:alpha:]., ]{2,}"))
names
## [1] "Moe Szyslak"          "Burns, C. Montgomery" "Rev. Timothy Lovejoy"
## [4] "Ned Flanders"         "Simpson, Homer"       "Dr. Julius Hibbert"

##3.1

# Sort so every name is in the same order
name <- str_replace_all(names, "(.+)(, .+)$", "\\2 \\1")  
name 
## [1] "Moe Szyslak"           ", C. Montgomery Burns" "Rev. Timothy Lovejoy" 
## [4] "Ned Flanders"          ", Homer Simpson"       "Dr. Julius Hibbert"
 # Removes commas
name1 <- str_replace_all(name, ", ", "")
name1
## [1] "Moe Szyslak"          "C. Montgomery Burns"  "Rev. Timothy Lovejoy"
## [4] "Ned Flanders"         "Homer Simpson"        "Dr. Julius Hibbert"
 # Removes name prefex
name2 <- str_replace_all(name1, "[A-Z][a-z]([a-z]?)\\.", "")
name2
## [1] "Moe Szyslak"         "C. Montgomery Burns" " Timothy Lovejoy"   
## [4] "Ned Flanders"        "Homer Simpson"       " Julius Hibbert"

##3.2

dataf <- data.frame(name2)
dataf$title <- str_detect(string = name2, pattern = "\\w{2,3}\\.")
kable(dataf)
name2 title
Moe Szyslak FALSE
C. Montgomery Burns FALSE
Timothy Lovejoy FALSE
Ned Flanders FALSE
Homer Simpson FALSE
Julius Hibbert FALSE

3.3

dataf$secname <- str_detect(string = name2, pattern = "[A-Z]{1}\\.")
kable(dataf)
name2 title secname
Moe Szyslak FALSE FALSE
C. Montgomery Burns FALSE TRUE
Timothy Lovejoy FALSE FALSE
Ned Flanders FALSE FALSE
Homer Simpson FALSE FALSE
Julius Hibbert FALSE FALSE

Problem 4

imgage2 <- "C:/Users/jpsim/Documents/DATA Acquisition and Management/3.4.png"
include_graphics(imgage2)

##4.1

fig1 <- "My phone bill is $90 or is it 90$"
str_extract_all(fig1, "[0-9]+\\$")
## [[1]]
## [1] "90$"

##4.2

fig2 <- "The amount of four letter words or less that are in this sentence are."
str_extract_all(fig2, "\\b[a-z]{1,4}\\b")
## [[1]]
## [1] "of"   "four" "or"   "less" "that" "are"  "in"   "this" "are"

##4.3

fig3 <- "This is really cool dude.txt\n"
str_extract_all(fig3, ".*?\\.txt$")
## [[1]]
## [1] "This is really cool dude.txt"

##4.4

fig4 <- "My date of birth is not 01/01/1911?"
str_extract_all(fig4, "\\d{2}/\\d{2}/\\d{4}")
## [[1]]
## [1] "01/01/1911"

##4.5

text = "<Header>text</head><body>text</body>"
form= "<(.+?)>.+?</\\1>" 
str_extract(text, form) 
## [1] "<body>text</body>"

Problem 9

imgage2 <- "C:/Users/jpsim/Documents/DATA Acquisition and Management/3.9.png"
include_graphics(imgage2)

encrypt = "kfgnrejngernmgfdgnjrgIFvjdsjfwndfdffsdfgghhtuyYdsfsdfsdafdfsdafasdfdfeOferwrtfrefwfscsdUfawfrefarfrfCfasdfdfafdfAfasdfdfasdfdsafdsafNfdasfvafdgvthgyytRbtyhythtyhjtyjtyEjtyurytjkuykyuikAykuuyukyukuykirthDgersretgtrgTgrtgtrgtHgrewgdhbgIhytjutyjSnytytjnytrwhMgertwgttrgYjytujyturjyujCgregtrtrhgrOhrtwhrthytrDgerrgrthgEgergwrtegWgreergterOgererwgRgerrbvrtbKfreefferwSvbwtrgbrttrtr"

form = "[[:upper:].]+"

#finds hidden letters
str_replace_all(paste(unlist(str_extract_all(encrypt, form)),collapse=""),pattern="[\\.]+",replacement=" ")
## [1] "IFYOUCANREADTHISMYCODEWORKS"
decrypt<- str_extract_all(encrypt, "[ [:upper:] !]")

cat(unlist(decrypt))
## I F Y O U C A N R E A D T H I S M Y C O D E W O R K S