R Cheat Sheets (Page 2 of 4) in pdf

Apply

apply(data, axis, fun)

Apply the function fun to data along axis

lapply(data, fun)

Apply the function fun to the list or vector data

rapply(data, fun, how)

Apply the function fun to data depending on the value of how

For a great introduction to using apply see

this

article.

I/O

read.table(“filename”, sep=”,”)

Reads information in from file with a variable delimiter

read.csv()

Read csv file into dataframe

fromJSON()

Read JSON formatted file or string into a list

xmlTreeParse()

Read XML formatted file or string into a list

write.csv()

Writes a dataframe or matrix (or tries to convert input to one) and writes to csv

Structures

data.frame(…)

Takes multiple variables with the same number of rows and creates a dataframe

list(name=var)

R’s implementation of a hash, takes multiple variables or variable tag pairs

ts(data, frequency)

Creates a regularly spaced time series object

Time Series

Time Series Classes

ts(data, frequency)

From R base, handles regularly spaced time series

zoo(data, index)

Part of the zoo package, handles irregularily spaced data using arbitrary time

date classes

xts(data, index)

Modification to zoo, gives more power to selecting date subsets

tis()

Uses POSIXct time stamps

irts()

From the package tseries and uses POSIXct time stamps

timeSeries()

Uses timeDate time stamps

Tests

adf.test

Computes the Augmented Dickey-Fuller test for the null that the series

has a unit root

jarque.bera.test

Tests the null of normaility for the series using the Jarque-Bera test statistics

kpss.test

Computes the KPSS test for the null that the series is level or trend stationary

po.test

Computes the Phillips-Ouliaris test for the null that the series in not cointegrated

pp.test

Computes the Phillips-Perron test for the null that the series has a unit root

runs.test

Computes the runs test for randomness of the binary series

terasvirta.test

Generically computes Teraesvirta’s neural network test for neglected

nonlinearity for the time series

white.test

Generically computes the White neural network test for neglected

nonlinearity for the time series

box.test

Compute the Box-Pierce or Ljung-Box test statistics for examining the null of independence

in a given series

R Cheat Sheets Page 2

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