Using R in Jupyter notebooks.

-- see the file on Using Python in Jupyter for some basics on Jupyter. This file is only about the R language.

R knows about integers, floating point numbers, even complex numbers like 1+2i.



In [1]:

    
2+2



In [2]:

    
sin(.1)









    




0.0998334166468282



In [6]:

    
1i*1i









    




-1+0i



In [9]:

    
(1+2i)*(2+3i)









    




-4+7i

A vector is a concatenation of numbers, so use the c operator for form the vector.

A variable can be assigned using either the equals sign, or the assignment arrow.



In [14]:

    
x <- c(10.4, 5.6, 3.1, 6.4, 21.7)



In [11]:

    
x



In [15]:

    
y = c(x,2,2,x)



In [16]:

    
y

R has a funny way of adding vectors of different lengths. It just recycles the entries from the shorter vector.



In [18]:

    
x+y









    



Warning message in x + y:
“longer object length is not a multiple of shorter object length”





    





	20.8
	11.2
	6.2
	12.8
	43.4
	12.4
	7.6
	13.5
	12
	24.8
	16.8
	27.3



In [19]:

    
1/x









    





	0.0961538461538461
	0.178571428571429
	0.32258064516129
	0.15625
	0.0460829493087558



In [20]:

    
y/x









    



Warning message in y/x:
“longer object length is not a multiple of shorter object length”





    





	1
	1
	1
	1
	1
	0.192307692307692
	0.357142857142857
	3.35483870967742
	0.875
	0.142857142857143
	0.615384615384615
	3.875



In [21]:

    
mean(x)



In [22]:

    
var(x)



In [23]:

    
# a direct way to compute the variance
sum((x-mean(x))^2)/(length(x)-1)

Matrices

Be careful with matrices. They are treated as lists of numbers, with a dimension attached.

The star operator does a entry-by-entry multiplication, which is NOT matrix multiplication.

For matrix multiplication, use

m %*% m



In [24]:

    
m = array(c(1,2,3,4),dim=c(2,2))



In [25]:

    
m



In [26]:

    
det(m)

-2



In [27]:

    
m*m



In [28]:

    
m%*%m



In [29]:

    
m^2

Plotting



In [31]:

    
plot(c(1,2,3,4))



In [32]:

    
# Define 2 vectors
cars <- c(1, 3, 6, 4, 9)
trucks <- c(2, 5, 4, 5, 12)

# Graph cars using a y axis that ranges from 0 to 12
plot(cars, type="o", col="blue", ylim=c(0,12))

# Graph trucks with red dashed line and square points
lines(trucks, type="o", pch=22, lty=2, col="red")

# Create a title with a red, bold/italic font
title(main="Autos", col.main="red", font.main=4)

Going further

Here is a good reference to the R language, which I've just been following along as I learn it in Jupyter.

An Introduction to R



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