Introduction¶
This chapter gives on overview of the book, but also introduces some fundamental concepts, such as objects, variables, and workspaces; saving and loading variables and objects; and R-scripts. Below is the supporting material for the sections of the chapter.
Variables and Objects¶
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Script file:
variables.R# Defining two variables a <- 1 b <- 2 # Entering the name leads to printing the content of the variable a # Showing the variables defined: ls() # Removing variables: rm(a,b) # Checking the existence of a variable exists("a") # Defining and removing "hidden" variables a <- 1 b <- 2 x <- 3 y <- 4 z <- 42 .zzyx <- 1412 rm(list=ls()) ls() ls(all=TRUE)
Saving and loading Objects¶
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Script file:
saving-and-loading-objects.R# In this example we create the two variables 'a' and 'b': a <- 1 b <- 1 # We save them in the data file "ab.RData" save(a,b,file="ab.RData") # We then remove the two variables: rm(a,b) # With then load the data file load("ab.RData") # and verify that the two variables are restored a b
Working with R-scripts¶
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Script file:
running-scripts.R## Running a script with and without echo source("source-echo-demo.R") source("source-echo-demo.R",echo=TRUE)
Additional script file:
source-echo-demo.Rcat("Hello world!\n") a <- 1 b <- 2 a print(a) b show(b)