Publications by Joey Campbell
repetition37_demo
suppressPackageStartupMessages(library("tidyverse")) package 㤼㸱tidyverse㤼㸲 was built under R version 3.6.3 1 Describe the equivalents of ?, +, * in {m,n} form. Pattern {m,n} Meaning ? {0,1} Match at most 1 + {1,} Match 1 or more * {0,} Match 0 or more Pattern {m,n} Meaning ? {0,1} Match at most 1 + {1,} Match 1 or more * {0,} Match 0...
5317 sym R (821 sym/14 pcs) 1 tbl
backref38_demo
suppressPackageStartupMessages(library("tidyverse")) package 㤼㸱tidyverse㤼㸲 was built under R version 3.6.3 1. Describe, in words, what these expressions will match: (.)\1\1: The same character appearing three times in a row. E.g. "aaa" "(.)(.)\\2\\1": A pair of characters followed by the same pair of characters in reversed order. E.g. "...
4153 sym R (1453 sym/12 pcs)
anchors35_demo
suppressPackageStartupMessages(library("tidyverse")) package 㤼㸱tidyverse㤼㸲 was built under R version 3.6.3 1. How would you match the literal string “\(^\)”? To check that the pattern works, I’ll include both the string “\(^\)”, and an example where that pattern occurs in the middle of the string which should not be matched. st...
2151 sym R (670 sym/8 pcs)
stringBasics33_demo
suppressPackageStartupMessages(library("tidyverse")) package 㤼㸱tidyverse㤼㸲 was built under R version 3.6.3 1. In code that doesn’t use stringr, you’ll often see paste() and paste0(). What’s the difference between the two functions? What stringr function are they equivalent to? How do the functions differ in their handling of NA? Th...
8008 sym R (1329 sym/38 pcs)
basicMatches34_demo
suppressPackageStartupMessages(library("tidyverse")) package 㤼㸱tidyverse㤼㸲 was built under R version 3.6.3 1. Explain why each of these strings don’t match a \: "\", "\\", "\\\". "\": This will escape the next character in the R string. "\\": This will resolve to \ in the regular expression, which will escape the next character in the...
2140 sym R (539 sym/5 pcs)
keys30_demo
suppressPackageStartupMessages(library("tidyverse")) package 㤼㸱tidyverse㤼㸲 was built under R version 3.6.3 suppressPackageStartupMessages(library("nycflights13")) package 㤼㸱nycflights13㤼㸲 was built under R version 3.6.3 1. Add a surrogate key to flights. I add the column flight_id as a surrogate key. I sort the data prior to maki...
171920 sym R (3510 sym/24 pcs) 3 img
filteringjoins32_demo
suppressPackageStartupMessages(library("tidyverse")) package 㤼㸱tidyverse㤼㸲 was built under R version 3.6.3 suppressPackageStartupMessages(library("nycflights13")) package 㤼㸱nycflights13㤼㸲 was built under R version 3.6.3 suppressPackageStartupMessages(library("viridis")) package 㤼㸱viridis㤼㸲 was built under R version 3.6.2 ...
17831 sym R (2468 sym/25 pcs) 1 img
mutatejoin31_demo
suppressPackageStartupMessages(library("tidyverse")) package 㤼㸱tidyverse㤼㸲 was built under R version 3.6.3 suppressPackageStartupMessages(library("nycflights13")) package 㤼㸱nycflights13㤼㸲 was built under R version 3.6.3 suppressPackageStartupMessages(library("viridis")) package 㤼㸱viridis㤼㸲 was built under R version 3.6.2 f...
11028 sym R (3231 sym/16 pcs) 6 img
nycflights13_29_demo
suppressPackageStartupMessages(library("tidyverse")) package 㤼㸱tidyverse㤼㸲 was built under R version 3.6.3 suppressPackageStartupMessages(library("nycflights13")) package 㤼㸱nycflights13㤼㸲 was built under R version 3.6.3 1. Imagine you wanted to draw (approximately) the route each plane flies from its origin to its destination. Wh...
145417 sym R (935 sym/7 pcs) 2 img
missing27_demo
1. Compare and contrast the fill arguments to spread() and complete(). In spread(), the fill argument explicitly sets the value to replace NAs. In complete(), the fill argument also sets a value to replace NAs but it is named list, allowing for different values for different variables. Also, both cases replace both implicit and explicit missing v...
1511 sym