Survival kit

Special characters

Some characters are somewhat difficult to write on the Czech keyboard:

Character	Shortcut	Alterantive
#	Alt + 35	Alt + x
$	Alt + 36	Alt + ů
&	Alt + 38	Alt + c
~	Alt + 126	Alt + +
|		Alt + w
>		Alt + .
{}		Alt + b/n
[]		Alt + f/g
`		Alt + ý + Space
^	Alt + 94

RStudio shortcuts

Sign/Action	Shortcut
->	Ctrl + Alt + -
%>%	Ctrl + Shift + m
run selected row	Ctrl + Enter
run whole script	Ctrl + Shift + Enter
comment line	Ctrl + Shift + c
insert section	Ctrl + Shift + r

Function reference

code description

Basics

install.packages("packagename") installs a package
library(packagename) attaches a package from a library

Getting help on anything:
?function equals help(function)
??function

Lookign at data:
head(x) and tail(x)
View(x)

Summary functions

mean(x) returns mean meadian(x) returns median

Data manipulation with dplyr

load package library(dplyr)

%>% pipe operator, x %>% f() equals f(x), allows chaining functions in a pipeline
(in newer versions of R, there is a native pipe operator |>)

count(data) count how many observations there are in a data frame
summarise(data,...) applies summary functions to a data frame
group_by(data, x) group data by values in variable x

Chain this for example like this:

data %>%
  group_by(y) %>% 
  summarise(prumer = mean(x),
            median = median(x))

Plotting with ggplot2

Load package library(ggplot2).
Alert: in ggplot2, individual pieces of code are chained using +!

ggplot() basic function call for each plot
aes(x, y, color, fill...) aesthetics

Geometries

geom_histogram() produces histogram
geom_point() produces scatterplot

Create a plot like this:

data %>%
  ggplot() +
  aes(x) +
  geom_histogram()