Chapter 4. Workflow: basics

R4DS github reference: r4ds/workflow-basics.Rmd

As a prerequisite install the tidyverse package.

if (!require("tidyverse")) install.packages("tidyverse")
library(tidyverse)

Question 1: Why does this code not work? Look carefully! (This may seem like an exercise in pointlessness, but training your brain to notice even the tiniest difference will pay off when programming.)

my_variable <- 10
my_varıable

## [1] 10

In fact the two variables are different: the seventh character is not a classical “i”. At first glance they seems to be equal but they’re not.

Question 2: Tweak each of the following R commands so that they run correctly:

library(tidyverse)
ggplot(dota = mpg) + 
  geom_point(mapping = aes(x = displ, y = hwy))
    
fliter(mpg, cyl = 8)
filter(diamond, carat > 3)

Here’s the fixed chunk: dota –> data, fliter –> filter, cyl = 8 –> cyl == 8 and diamond –> diamonds.

library(tidyverse)
ggplot(data = mpg) + 
  geom_point(mapping = aes(x = displ, y = hwy))

filter(mpg, cyl == 8)

## # A tibble: 70 x 11
##    manufacturer model displ  year   cyl trans drv     cty   hwy fl    class
##    <chr>        <chr> <dbl> <int> <int> <chr> <chr> <int> <int> <chr> <chr>
##  1 audi         a6 q~   4.2  2008     8 auto~ 4        16    23 p     mids~
##  2 chevrolet    c150~   5.3  2008     8 auto~ r        14    20 r     suv  
##  3 chevrolet    c150~   5.3  2008     8 auto~ r        11    15 e     suv  
##  4 chevrolet    c150~   5.3  2008     8 auto~ r        14    20 r     suv  
##  5 chevrolet    c150~   5.7  1999     8 auto~ r        13    17 r     suv  
##  6 chevrolet    c150~   6    2008     8 auto~ r        12    17 r     suv  
##  7 chevrolet    corv~   5.7  1999     8 manu~ r        16    26 p     2sea~
##  8 chevrolet    corv~   5.7  1999     8 auto~ r        15    23 p     2sea~
##  9 chevrolet    corv~   6.2  2008     8 manu~ r        16    26 p     2sea~
## 10 chevrolet    corv~   6.2  2008     8 auto~ r        15    25 p     2sea~
## # ... with 60 more rows

filter(diamonds, carat > 3)

## # A tibble: 32 x 10
##    carat cut     color clarity depth table price     x     y     z
##    <dbl> <ord>   <ord> <ord>   <dbl> <dbl> <int> <dbl> <dbl> <dbl>
##  1  3.01 Premium I     I1       62.7    58  8040  9.1   8.97  5.67
##  2  3.11 Fair    J     I1       65.9    57  9823  9.15  9.02  5.98
##  3  3.01 Premium F     I1       62.2    56  9925  9.24  9.13  5.73
##  4  3.05 Premium E     I1       60.9    58 10453  9.26  9.25  5.66
##  5  3.02 Fair    I     I1       65.2    56 10577  9.11  9.02  5.91
##  6  3.01 Fair    H     I1       56.1    62 10761  9.54  9.38  5.31
##  7  3.65 Fair    H     I1       67.1    53 11668  9.53  9.48  6.38
##  8  3.24 Premium H     I1       62.1    58 12300  9.44  9.4   5.85
##  9  3.22 Ideal   I     I1       62.6    55 12545  9.49  9.42  5.92
## 10  3.5  Ideal   H     I1       62.8    57 12587  9.65  9.59  6.03
## # ... with 22 more rows

Question 3: Press Alt + Shift + K. What happens? How can you get to the same place using the menus?

This keys combination shows the Keyboard Shortcut Quick Reference. The same reference can be obtained from the Tools menu (eight item).