c() |
Combines values into a vector |
c(4, 5, 7, 9) |
mean() |
Computes the mean of a variable/vector |
mean(my_numbers) |
install.packages() |
Installs a package |
install.packages("lubridate") |
library() |
Loads a package into the session |
library("lubridate") |
Sys.Date() |
Returns today’s date |
today <- Sys.Date() |
as.Date() |
Converts a string into a Date object |
as.Date("2024-06-28") |
time_length() |
Computes length of a time difference |
time_length(birthday - today) |
abs() |
Returns absolute value |
abs(time_difference) |
read.table() |
Reads tabular data from a file or URL |
read.table(url, sep=",", header=FALSE, ...) |
class() |
Tells the object type/class |
class(iris_data) |
head() |
Shows the first rows of a dataset |
head(iris_data) |
sd() |
Computes sample standard deviation |
sd(iris_data$Sepal.Length) |
summary() |
Gives summary statistics |
summary(iris_data) |
stem() |
Makes a stem-and-leaf plot |
stem(iris_data$Sepal.Length) |
hist() |
Makes a histogram |
hist(iris_data$Sepal.Length) |
boxplot() |
Makes a boxplot |
boxplot(iris_data$Sepal.Length) |
plot() |
Makes a plot/scatterplot |
plot(iris_data$Sepal.Length, iris_data$Petal.Length) |
pdf() |
Opens a PDF graphics device to save plots |
pdf("box.pdf") |
dev.off() |
Closes the graphics device |
dev.off() |
log() |
Applies log transformation |
log(maas$lead) |
which() |
Returns row positions meeting a condition |
which(maas$lead > 450) |
unique() |
Removes duplicate values |
unique(c(...)) |
map() |
Draws a map from the maps package |
map("county", "ca", add=TRUE) |
points() |
Adds points to an existing plot |
points(b$x, b$y, cex=b$o3/mean(b$o3)) |
cut() |
Splits numeric values into intervals/groups |
cut(b$o3, c(...)) |
as.numeric() |
Converts an object to numeric form |
as.numeric(AQI_levels) |
hist(mtcars$mpg)
boxplot(mtcars$mpg, horizontal = TRUE, add=T)
maas <- read.table("http://www.stat.ucla.edu/~nchristo/statistics12/soil.txt", header=TRUE)
head(maas)
## x y lead zinc
## 1 181072 333611 299 1022
## 2 181025 333558 277 1141
## 3 181165 333537 199 640
## 4 181298 333484 116 257
## 5 181307 333330 117 269
## 6 181390 333260 137 281
url <- "https://archive.ics.uci.edu/ml/machine-learning-databases/iris/iris.data"
iris_data <- read.table(
url,
sep = ",",
header = FALSE,
col.names = c(
"Sepal.Length",
"Sepal.Width",
"Petal.Length",
"Petal.Width",
"Species"
)
)
head(iris_data)
## Sepal.Length Sepal.Width Petal.Length Petal.Width Species
## 1 5.1 3.5 1.4 0.2 Iris-setosa
## 2 4.9 3.0 1.4 0.2 Iris-setosa
## 3 4.7 3.2 1.3 0.2 Iris-setosa
## 4 4.6 3.1 1.5 0.2 Iris-setosa
## 5 5.0 3.6 1.4 0.2 Iris-setosa
## 6 5.4 3.9 1.7 0.4 Iris-setosa