List Vol.2 Exercises

Answers to the exercises are available here.

Exercise 1

Consider 3 vectors, day, month and year:

year=c(2005:2016) month=c(1:12) day=c(1:31)

Define a list Date such as:
Date=

$year
[1] 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016

$month
[1] 1 2 3 4 5 6 7 8 9 10 11 12

$day
[1] 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

Exercise 2

write an R statement that will replace the values of year element in Date list for c(2000:2010).

Exercise 3

write an R statement that will delete the value 4 of the month component of the list Date.

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Learn more about lists in the online courses:

• Learn By Example: Statistics and Data Science in R (lecture 59)
• The Comprehensive Statistics and Data Science with R Course (lectures 69-76)
  
• R Programming: Advanced Analytics In R For Data Science (11 lectures all about lists, ~ 1.5 hrs in total)

Exercise 4

Consider a vector x such that:
x=c(1,3,4,7,11,18,29)
Write an R statement that will return a list X2 with components of value:
x*2,x/2,sqrt(x) and names "x*2","x/2","sqrt(x)"

Exercise 5

Consider the X2 list.
Write an R statement that will return a vector:
2.000000 2.645751 3.316625

Exercise 6

Write an R statement that will return a concatenation M, of Date and X2 lists.
M $year [1] 2000 2001 2002 2003 2004 2005 2006 2007 2008

$month
[1] 1 2 3 5 6 7 8 9 10 11 12

$day
[1] 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
[24] 24 25 26 27 28 29 30 31

$`x*2`
[1] 2 6 8 14 22 36 58

$`x/2`
[1] 0.5 1.5 2.0 3.5 5.5 9.0 14.5

$`sqrt(x)`
[1] 1.000000 1.732051 2.000000 2.645751 3.316625 4.242641 5.385165

Exercise 7

Write an R statement that will return a sublist N of M, with components year,x*2 and day.

Exercise 8

Consider the N list.
Write an R statement that will return:
-the length of x*2 vector in N
-the value of the second element of vector year in N

Exercise 9

Consider 3 letters vectors, and 2 numeric vectors:
A=letters[1:4],B=letters[5:10],C=letters[11:15]
D=c(1:10),E=c(20:5)

Define a list z, with elementes x and y,such that
x is a list with elements A,B,and C;
and y is alist with elements D and E.

Exercise 10
Write an R statement that will return:
-the number on third position on the second vector of the first list of z
-the letter on fifth position on the third vector of the second list of z

Want some extra practice with lists? Please take a look here