DS607 - Homework 3

Homework 3

1. Using the 173 majors listed

In fivethirtyeight.com’s College Majors dataset [https://fivethirtyeight.com/features/the-economic-guide-to-picking-a-college-major/], provide code that identifies the majors that contain either “DATA” or “STATISTICS”

library(tidyverse)

theURL <- "https://raw.githubusercontent.com/fivethirtyeight/data/master/college-majors/majors-list.csv"
all_majors <- read.csv(file=theURL, fileEncoding="UTF-8-BOM")
data_or_stats <- subset(all_majors, grepl("DATA|STATISTICS", Major))
data_or_stats

##    FOD1P                                         Major          Major_Category
## 44  6212 MANAGEMENT INFORMATION SYSTEMS AND STATISTICS                Business
## 52  2101      COMPUTER PROGRAMMING AND DATA PROCESSING Computers & Mathematics
## 59  3702               STATISTICS AND DECISION SCIENCE Computers & Mathematics

2. Write code that transforms the data below:

vector_1 <- c("bell pepper", "bilberry", "blackberry", "blood orange")
vector_2 <- c("blueberry", "cantaloupe", "chili pepper", "cloudberry")
vector_3 <- c("elderberry", "lime", "lychee", "mulberry")
vector_4 <- c("olive", "salal berry")
main_vector <- c(vector_1, vector_2, vector_3, vector_4)
main_vector

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

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

lista <- c("abba", "hello\2\1","aaaabbbcccdddde", "aabbmmmmmjmmkmkkk","banana", "amanaplanacanalpanama","civic", "racecar")
str_view(lista, "(.)\\1\\1")
str_view(lista, "(.)(.)\\2\\1")
str_view(lista, "(..)\\1")
str_view(lista, "(.).\\1.\\1")
str_view(lista, "(.)(.)(.).*\\3\\2\\1")

1. “(.)\1\1” Match any three repeated characters
2. "(.)(.)\2\1 Match any symmetrical 4 characters where 1st and 4th characters are the same and 2,3 are the same.
3. (..)\1 Match any repeated characters separated by 1 character.
4. “(.).\1.\1” match any three repeated characters separated by the same character
5. "(.)(.)(.).*\3\2\1" match palyndromes of 6 of more letters

4.Construct regular expressions to match words that:

Start and end with the same character. Contain a repeated pair of letters (e.g. “church” contains “ch” repeated twice.) Contain one letter repeated in at least three places (e.g. “eleven” contains three “e”s.)

words <- c("civic", "church", "eleven")
str_view(words, "^(.).*\\1$")
str_view(words, "(.)(.).*\\1\\2")
str_view(words, "(.).\\1.\\1")