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Difficulty level:

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.

**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**

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Ken says

(Tell me if I misunderstood it, thanks.)

There might be something wrong with exercise 10

-the number on third position on the second vector of the first list of z

##first list of z don’t have numbers, but letters

-the letter on fifth position on the third vector of the second list of z

##second list of z neither have letters nor third vector

Output of z from exercise 9 is :

[[1]]

[[1]][[1]]

[1] “a” “b” “c” “d”

[[1]][[2]]

[1] “e” “f” “g” “h” “i” “j”

[[1]][[3]]

[1] “k” “l” “m” “n” “o”

[[2]]

[[2]][[1]]

[1] 1 2 3 4 5 6 7 8 9 10

[[2]][[2]]

[1] 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5

Kasp93 says

You’re perfectly right, there’s a mistake.