R functions and keyboard shortcuts

R functions/commands and keyboard shortcuts

R! is powerful and has rich packages and functions. It's impossible to build a list of functions/shortcuts to fit the purposes of all. Below are some functions/shortcuts related to my projects.

• Cheatsheets, The R Guide, R Reference Card
• Help functions: help()/?, apropos(), find(): apropos() finds all objects. find() the locations of found objects, methods(), example(), demo(), vignette(), args() 
• Housekeeping functions: getwd(), setwd(), rm(list=ls()) removes all objects in the R environment, source("myRscript.r") runs the R codes in "myRscript.r" file, fix() modifies the original object, and edit() is used edit an object and returns to a new object, download.file() downloads a file from the Internet, attach()/detach() objects, search() shows the current search paths and sequence, install.packages(), update.packages(), remove.packages(), getOption("defaultPackages") which can be changed by setting the option in startup code (e.g. in ~/.Rprofile), .libPaths()
• Numeric/character functions: length(), seq(), rep(), cut(), pretty(), cat(), substr(), grep(), sub(), strsplit(), paste(), toupper(), tolower()
• Data functions: read.table(), head(), tail(), str(), class(), length(), dim(), nrow(), ncol(), names(), levels(), length(), c(), cbind(), rbind(), append(), rep(), rev(), sort(), unique()
• Type functions: "is." for checking or "as." for conversion + numeric(), character(), vector(), matrix(), data.frame(), factor(), logical(), integer(). For example: is.numeric(), as.numeric()
• Mathematical functions: abs(), sqrt(), log(), log(x, base=n), log10(), exp(), prod(), factorial(), choose(), ceiling(), floor(), solve(), trunc(), round(), signif(), cos(), sin(), tan(), acos()
• Statistical functions: mean(), median(), sd(), var(), mad(), quantile(), range(), sum(), diff(), min(), max(), scale(), fivenum(), cumsum(), cumprod(), cummax(), cumin(), cor(), colSums(), rowSums(), colMeans(), rowMeans()
• Probability functions: the form is [d][p][q][r]distribution(). d, p, q, r are for (d)ensity, cumulated (p)robability/distribution function, (q)uantile function, and (r)andom generation, respectively. the Distribution types can be: (norm)al, (beta), (binom)ial, (chisq)uared, (exp)onential, (logis)tic, (multinom)ial, (n)egative (binom)ial, (pois)son, (f), (gamma), (t), (unif)orm, etc. for example: dnorm(), pnorm(), qnorm(), rnorm()
• Statistical modeling functions
• Model functions: lm(), glm(), nls(), nls2(), lme() / nlme()
• Symbol formulas (y ~ A + B + C ): ":" is for interaction term, "*" is for complete interaction, "^" is for crossing to a specified degree "." is a placeholder for all other variables except the dependent variable, "-" removes a variable from the equation, "-1" suppresses the intercept, "I()" has elements within the parentheses interpreted arithmetically
• Post-estimation functions: coef(), confint(), resid(), fitted(), summary(), predict(), deviance(), print(),plot(), formula(), anova(obj1, obj2), AIC(), vcov()
• Contrast functions: contr.helmert(), contr.poly(), contr.sum(), contr.treatment(), contr.SAS()
• RStudio is an integrated development environment (IDE) for R. RStudio combines an intuitive user interface with powerful coding tools to help you get the most out of R. Shortcuts (you can modify them: Tools -> Modify Keyboard Shortcuts...)
• Alt + Shift + K: Show a Quick Reference
• Alt + -: Insert assignment operator "<- font="">
• Ctrl + Shift + M: Insert pipe operator "%>%" (I changed it as Ctrl + Shift + P)
• Ctrl + Alt + I: Insert chunk (R Notebook/Markdown)
• Ctrl + 1: Move cursor to source Editor window
• Ctrl + 2: Move cursor to Command window
• Ctrl + 3: Move cursor to Help window
• Ctrl + 4: Move cursor to History window
• Ctrl + 5: Move cursor to File window
• Ctrl + 6: Move cursor to Plots window
• ...