Question 1 The 173 majors listed in fivethirtyeight.com’s College Majors dataset [https://fivethirtyeight.com/features/the-economic-guide-to-picking-a-college-major/], was pulled from [https://github.com/fivethirtyeight/data/blob/master/college-majors/majors-list.csv]
library(readr)
urlfile = "https://raw.githubusercontent.com/fivethirtyeight/data/master/college-majors/majors-list.csv"
majors <- read_csv(url(urlfile))## Rows: 174 Columns: 3## -- Column specification --------------------------------------------------------
## Delimiter: ","
## chr (3): FOD1P, Major, Major_Category##
## i Use `spec()` to retrieve the full column specification for this data.
## i Specify the column types or set `show_col_types = FALSE` to quiet this message.spec(majors)## cols(
## FOD1P = col_character(),
## Major = col_character(),
## Major_Category = col_character()
## )Code identification of majors that contain either “DATA” or “STATISTICS”
library(stringr)
majors1 <- majors %>%
filter(str_detect(majors$Major, "DATA") | str_detect(majors$Major, "STATISTICS"))
majors1## # A tibble: 3 x 3
## FOD1P Major Major_Category
## <chr> <chr> <chr>
## 1 6212 MANAGEMENT INFORMATION SYSTEMS AND STATISTICS Business
## 2 2101 COMPUTER PROGRAMMING AND DATA PROCESSING Computers & Mathematics
## 3 3702 STATISTICS AND DECISION SCIENCE Computers & MathematicsQuestion 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”)
x <- c("bell pepper", "bilberry", "blackberry", "blood orange", "blueberry", "cantaloupe", "chili pepper", "cloudberry", "elderberry", "lime", "lychee", "mulberry", "olive", "salal berry")
print(x)## [1] "bell pepper" "bilberry" "blackberry" "blood orange" "blueberry"
## [6] "cantaloupe" "chili pepper" "cloudberry" "elderberry" "lime"
## [11] "lychee" "mulberry" "olive" "salal berry"Question 3 Describe, in words, what these expressions will match:
(.)\1\1 Response: This expression will match the same character appearing three times in a row.
“(.)(.)\2\1” Response: This expression will match a pair of characters with the same pair of characters in reversed order.
(..)\1 Response: This expression wil match any two characters that are repeated.
“(.).\1.\1” Response: This expression will match any character followed by any character, the original character, any character, then the original character.
"(.)(.)(.).*\3\2\1" Response: This expression will match any three characters, followed by zero, then followed by the same three characters in a reverse order.
Question 4
Construct regular expressions to match words that:
Start and end with the same character.
Response: "^(.)((.*\1\()|\\1?\))"
library(stringr)
str_subset(words, "^(.)((.*\\1$)|\\1?$)")## [1] "a" "america" "area" "dad" "dead"
## [6] "depend" "educate" "else" "encourage" "engine"
## [11] "europe" "evidence" "example" "excuse" "exercise"
## [16] "expense" "experience" "eye" "health" "high"
## [21] "knock" "level" "local" "nation" "non"
## [26] "rather" "refer" "remember" "serious" "stairs"
## [31] "test" "tonight" "transport" "treat" "trust"
## [36] "window" "yesterday"Contain a repeated pair of letters (e.g. “church” contains “ch” repeated twice.) Response: "([A-Za-z][A-Za-z]).*\1"
str_subset(words, "([A-Za-z][A-Za-z]).*\\1")## [1] "appropriate" "church" "condition" "decide" "environment"
## [6] "london" "paragraph" "particular" "photograph" "prepare"
## [11] "pressure" "remember" "represent" "require" "sense"
## [16] "therefore" "understand" "whether"Contain one letter repeated in at least three places (e.g. “eleven” contains three “e”s.) Response: “([a-z]).\1.\1”
str_subset(words, "([a-z]).*\\1.*\\1")## [1] "appropriate" "available" "believe" "between" "business"
## [6] "degree" "difference" "discuss" "eleven" "environment"
## [11] "evidence" "exercise" "expense" "experience" "individual"
## [16] "paragraph" "receive" "remember" "represent" "telephone"
## [21] "therefore" "tomorrow"Note that the echo = FALSE parameter was added to the code chunk to prevent printing of the R code that generated the plot.