These exercises are about the vector sections of Introduction to R.
Exercise 1
<- c(1,2,3,4,5)
x x
## [1] 1 2 3 4 5
<- 1:100
x x
## [1] 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
## [19] 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
## [37] 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
## [55] 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72
## [73] 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90
## [91] 91 92 93 94 95 96 97 98 99 100
<- seq(0,20,5)
x x
## [1] 0 5 10 15 20
<- c(rep(1,2),rep(2,2),rep(3,2))
x x
## [1] 1 1 2 2 3 3
<- c(rep(1,2),seq(5,9,2),10)
x x
## [1] 1 1 5 7 9 10
Exercise 2
<- 1:10
x x
## [1] 1 2 3 4 5 6 7 8 9 10
<- x[-c(1,length(x))]
y y
## [1] 2 3 4 5 6 7 8 9
<- x[-c(2,5)]
y y
## [1] 1 3 4 6 7 8 9 10
<- sqrt(x[6:7])
y y
## [1] 2.449490 2.645751
<- x[seq(1,10,2)]
y y
## [1] 1 3 5 7 9
Exercise 3
# Depend on current working directory..
length(dir())
## [1] 10
<- dir()
x 1] x[
## [1] "_course.yml"
Exercise 4
<- c("Gene_1", "Gene_2", "Gene_3","Gene_4")
geneNames <- c(1000, 3000, 10000, 12000)
expression <- c(100, 3000, 200, 1000)
geneLengths names(expression) <- geneNames
names(geneLengths) <- geneNames
expression
## Gene_1 Gene_2 Gene_3 Gene_4
## 1000 3000 10000 12000
geneLengths
## Gene_1 Gene_2 Gene_3 Gene_4
## 100 3000 200 1000
names(geneLengths[geneLengths == max(geneLengths)])
## [1] "Gene_2"
names(geneLengths[which.max(geneLengths)])
## [1] "Gene_2"
> 100 & expression > 10000] geneNames[geneLengths
## [1] "Gene_4"
<- expression/geneLengths
lne lne
## Gene_1 Gene_2 Gene_3 Gene_4
## 10 1 50 12
> mean(lne)] geneNames[lne
## [1] "Gene_3"