Basic R tryouts

basic.R

library('ggplot2')

#basics

3*4
2^3
1/2 + 1/2*sqrt(5)

#those two are identical
(1+2+3+4)/4
sum(1:4)/4

#load data
data(women)

#data frames basic
ladies = women

#inch is 2.54 cm
inch.for.meter =  2.54/100

#lengths in mt
ladies$lengthM = ladies$height * inch.for.meter

#kg  is 2.2046 pounds
pound.for.kg =  1/2.2046

#weight in kg
ladies$weightKg = ladies$weight * pound.for.kg  

#quetelet index
ladies$QueteletIdx = ladies$weightKg / ladies$lengthM^2  

#statistics
mean(ladies$QueteletIdx)
var(ladies$QueteletIdx)
median(ladies$QueteletIdx)

#scatterplot (weight vs length)
qplot(ladies$lengthM,ladies$weightKg)

#box plot
boxplot(ladies$QueteletIdx)

#basic vector
1:10
5:1

#sum of squares
x = 1:50
sum(x*x)

#bin
bin = 2 ^ (3:0) 
bin

#bin to dec
dec = sum(c(1,0,1,1)*bin)
dec

# runif
x =  runif(500)

#basic
hist(x)
plot(density(x))
rug(x)

# qplot vs ggplot check: 
# http://stackoverflow.com/questions/5322836/choosing-between-qplot-and-ggplot-in-ggplot2

#ggplot2 package: qplot
qplot(x, geom="histogram")

#ggplot2: using straight ggplot (requires conversion to data.frame)
ggplot(data.frame(x), aes(x)) + geom_histogram()