R Language

Published: by Creative Commons Licence

shortscut

  • Ctrl + Shift + N : new script
  • Tab : auto indent and auto complete
  • Ctrl + Shift + C : comment and uncomment
  • Ctrl + Enter : run current line
  • Ctrl + Shift + Enter : run all lines
  • Ctrl + A: select all
  • Shift + arrow : select text
  • Ctrl + D : delete line
  • Ctrl + Z : undo
  • Ctrl + Shift + Z : redo
  • Alt + - : assign to
  • Ctrl + I: auto indent
  • Ctrl + Shift + A : auto format
  • Ctrl + F : select and replace
  • Ctrl + Alt + X: extract function

foundation of syntax

data types

  • integer double complex character logical

Identifier Rules

  • a-z A-Z 0-9 _ .
  • case sensitive
  • cannot start with number or _
  • cannot be reserved words

operators

  • + - * / ^ %% %/%

  • == != > < >= <=

  • & | ! && ||

  • = -> <-

  • ( ) [ ] { }

  • :：create a sequence

  • ;：separate multiple statements

  • @：access localtion

  • ::：access variable

  • $: extract element

  • ~：formula

  • ?：help

  • %：custom operator

conditional statements

if (condition) {
    # do something
} else if (condition) {
    # do something
} else {
    # do something
}

ifelse(condition, true, false)

switch(expression, case1, case2, case3, ...)

switch(1, "a", "b", "c")

switch("a", a = "a", b = "b", c = "c")

loop statements

for (var in seq) {
    # do something
}


while (condition) {
    # do something
}

function

function_name <- function(arg1, arg2, ...) {
    # do something
    return (value)
}

# anonymous function
lapply(seq, function_name(x) {
    # do something
    return (value)
})

package

  • install.packages("package_name"): install package

  • library(package_name): load package

  • detach("package_name"): unload package

  • remove.packages("package_name"): remove package

awesome functions

  • abs(x): absolute value

  • sqrt(x): square root

  • ceiling(x): ceiling

  • floor(x): floor

  • trunc(x): truncate to integer

  • round(x, digits): round to digits

  • signif(x, digits): significant digits

  • cos(x) sin(x) tan(x): trigonometric functions

  • acos(x) asin(x) atan(x): inverse trigonometric functions

  • cosh(x) sinh(x) tanh(x): hyperbolic trigonometric functions

  • acosh(x) asinh(x) atanh(x): inverse hyperbolic trigonometric functions

  • log(x, base): log

  • log(x): natural log

  • log10(x): log10

  • exp(x): exponential

  • mean(x): mean

  • median(x): median

  • var(x): variance

  • sd(x): standard deviation

  • mad(x): median absolute deviation

  • range(x): range

  • min(x): minimum

  • max(x): maximum

  • sum(x): sum

  • diff(x, lag): difference between consecutive elements

  • quantile(x, probs): quantile of x

  • scale(x, center, scale): scale x