Data607 Assignment for Week 3

#1. Using the 173 majors listed in fivethirtyeight.com’s College Majors dataset, provide code that identifies the majors that contain either “DATA” or “STATISTICS”

majors <- read.csv(url('https://raw.githubusercontent.com/fivethirtyeight/data/master/college-majors/majors-list.csv'), stringsAsFactors = F)
str(majors)

## 'data.frame':    174 obs. of  3 variables:
##  $ FOD1P         : chr  "1100" "1101" "1102" "1103" ...
##  $ Major         : chr  "GENERAL AGRICULTURE" "AGRICULTURE PRODUCTION AND MANAGEMENT" "AGRICULTURAL ECONOMICS" "ANIMAL SCIENCES" ...
##  $ Major_Category: chr  "Agriculture & Natural Resources" "Agriculture & Natural Resources" "Agriculture & Natural Resources" "Agriculture & Natural Resources" ...

majors$Major[grepl('DATA', majors$Major)]

## [1] "COMPUTER PROGRAMMING AND DATA PROCESSING"

majors$Major[grepl('STATISTICS', majors$Major)]

## [1] "MANAGEMENT INFORMATION SYSTEMS AND STATISTICS"
## [2] "STATISTICS AND DECISION SCIENCE"

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#2 Write code that transforms the data below:

[1] “bell pepper” “bilberry” “blackberry” “blood orange”

[5] “blueberry” “cantaloupe” “chili pepper” “cloudberry”

[9] “elderberry” “lime” “lychee” “mulberry”

[13] “olive” “salal berry”

Into a format like this:

c(“bell pepper”, “bilberry”, “blackberry”, “blood orange”, “blueberry”, “cantaloupe”, “chili pepper”, “cloudberry”, “elderberry”, “lime”, “lychee”, “mulberry”, “olive”, “salal berry”)

blob <- '[1] "bell pepper"  "bilberry"     "blackberry"   "blood orange"

[5] "blueberry"    "cantaloupe"   "chili pepper" "cloudberry"  

[9] "elderberry"   "lime"         "lychee"       "mulberry"    

[13] "olive"        "salal berry"'

library(stringr)

foods <- str_extract_all(blob, '[a-z]+\\s[a-z]+|[a-z]+')
unlist(foods)

##  [1] "bell pepper"  "bilberry"     "blackberry"   "blood orange" "blueberry"   
##  [6] "cantaloupe"   "chili pepper" "cloudberry"   "elderberry"   "lime"        
## [11] "lychee"       "mulberry"     "olive"        "salal berry"

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#3 Describe, in words, what these expressions will match:

(.)\1\1

• This would match the string ‘\1\1’ and the character before it, as long as its not a new line

“(.)(.)\\2\\1”

• This would match anything like a 4 letter palindrome. one character, another character, the same as the 2nd character, the same as the first character, while surrounded by quotes.

(..)\1

• This would match any two characters followed by the string ‘\1’

“(.).\\1.\\1”

• This would match any character, then any other character, then the first character again, then any other character, then the first character again, while surrounded by quotes.

"(.)(.)(.).*\\3\\2\\1"

• This would match any three characters and any (maybe none) characters in between the first 3 characters reversed, while surrounded by quotes.

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#4 Construct regular expressions to match words that:

Start and end with the same character.

• (.)[a-z]*\\1

Contain a repeated pair of letters (e.g. “church” contains “ch” repeated twice.)

• ([a-z]{2})[a-z]*\\1

Contain one letter repeated in at least three places (e.g. “eleven” contains three “e”s.)

• [a-z]*([a-z])[a-z]*\\1[a-z]*\\1[a-z]*