Assignment 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”

Load the data from csv file and identify the majors that contain DATA and STATISTICS

majors <- read.csv("https://raw.githubusercontent.com/datasets/five-thirty-eight-datasets/master/datasets/college-majors/data/majors-list.csv")

temp <- majors$major

dt<-grepl("data", temp)       #identify majors containing DATA

temp[dt]

## [1] "computer programming and data processing"

st<-grepl("statistics", temp)   #identify majors containing STATISTICS

temp[st]

## [1] "management information systems and statistics"
## [2] "statistics and decision science"

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”)

s1 = c("bell pepper", "bilberry", "blackberry","blood orange")
s2 = c("blueberry","cantalope","chili pepper","cloudberry")
s3 = c("elderberry","lime","lychee","mulberry")
s4 = c("olive","salal berry")

berries <- c(s1,s2,s3,s4)
print(berries)

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

3.

Describe, in words, what these expressions will match:

1. (.)\1\1

A character will be repeated thrice. Example iii.

l <- c("abba","cac","aabb","absca","abcdefg","aaaaaa","iii","abab","i1221i","i123456721i","mpmnm","0101","acca")
str_view(l, "(.)\\1\\1", match = TRUE)

2. “(.)(.)\2\1”

One pair of characters will be repeated twice but the second time will be the reverse of the first. Example acca.

str_view(l, "(.)(.)\\2\\1", match = TRUE)

3. (..)\1

2 characters will be repeated. It can be any 2 characters. Example 0101.

str_view(l, "(..)\\1", match = TRUE)

4. “(.).\1.\1”

Example mpmnm. A character followed by another character then the first character again, then a new character followed by the first character again.

str_view(l, "(.).\\1.\\1", match = TRUE)

5. "(.)(.)(.).*\3\2\1"

In the beginning there are 3 characters and the same 3 characters are there in the end of the string but in the reverse order. In the middle there are zero or more characters. Example i123456721i or i1221i

str_view(l, "(.)(.)(.).*\\3\\2\\1", match = TRUE)

4.

Construct regular expressions to match words that:

1. Start and end with the same character.

"^(.).*\1$"

str_view(l, "^(.).*\\1$", match = TRUE)

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

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

str_view(berries, "(.)(.).*\\1\\2", match = TRUE)

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

“(.).\1.\1”

str_view(berries, "(.).*\\1.*\\1", match = TRUE)