R Cheat Sheet

R is a language and environment for statistical computing and data analysis. This R cheatsheet provides an example-driven reference covering core R syntax, data structures, functions, and commonly used base R operations.

Basic Usage

print("Hello, R")

# Comment

Variables

x <- 10
y = 20

z <- x + y

Basic Types

numeric
integer
character
logical
complex

typeof(10)
typeof("text")

Vectors

v <- c(1, 2, 3)

length(v)
v[1]
v[c(1, 3)]

v + 1

Sequences

1:10
seq(0, 1, by = 0.2)
rep(1, times = 5)

Logical Operations

v > 2
v == 2
v != 1

TRUE & FALSE
TRUE | FALSE
!TRUE

Control Flow

if / else

if (x > 10) {
  "large"
} else {
  "small"
}

for

for (i in 1:5) {
  print(i)
}

while

while (x > 0) {
  x <- x - 1
}

Functions

add <- function(a, b) {
  a + b
}

add(2, 3)

Default Arguments

power <- function(x, p = 2) {
  x ^ p
}

Anonymous Functions

(function(x) x * x)(5)

Data Frames

df <- data.frame(
  name = c("A", "B"),
  age = c(20, 30)
)

df$name
df[1, ]
df[, "age"]

Factors

f <- factor(c("low", "high", "low"))
levels(f)

Lists

lst <- list(
  a = 1,
  b = "text",
  c = TRUE
)

lst$a
lst[[2]]

Matrices

m <- matrix(1:6, nrow = 2)

m[1, 2]
dim(m)

Apply Family

apply(m, 1, sum)
apply(m, 2, mean)

lapply(lst, length)
sapply(lst, length)

Sorting

sort(v)
order(v)

Subsetting

v[v > 2]
df[df$age > 20, ]

Missing Values

NA
is.na(v)

na.omit(c(1, NA, 3))

String Functions

paste("Hello", "World")
paste0("A", "B")

substr("abcdef", 1, 3)
nchar("text")

Dates

Sys.Date()
Sys.time()

as.Date("2025-01-01")

Math Functions

sum(v)
mean(v)
median(v)
sd(v)

round(3.14159, 2)

Random Numbers

runif(5)
rnorm(5)
set.seed(123)

File I/O

write.csv(df, "data.csv")
read.csv("data.csv")

Packages

install.packages("ggplot2")
library(ggplot2)

Help & Documentation

?mean
help(sum)