Suppose x = 1.1, a = 2.2, and b = 3.3. Assign each expression to the value of the variable z and print the value stored in z.
x <- 1.1
a <- 2.2
b <- 3.3
z <- x^{a^b}
print(z)
## [1] 3.61714
x <- 1.1
a <- 2.2
b <- 3.3
z <- (x^a)^b
print(z)
## [1] 1.997611
x <- 1.1
a <- 2.2
b <- 3.3
z <- (3*(x^3))+2*(x^2)+1
print(z)
## [1] 7.413
Using the rep
and seq
functions, create the
following vectors:
a <- seq(from = 1, to = 7, by = 1)
b <- seq(from = 8, to = 1, by = -1)
z <- c(a,b)
print(z)
## [1] 1 2 3 4 5 6 7 8 7 6 5 4 3 2 1
my_vec<- c(1,2,3,4,5)
rep(x=my_vec, time=my_vec)
## [1] 1 2 2 3 3 3 4 4 4 4 5 5 5 5 5
my_vec<-c(5,4,3,2,1)
rep(x=my_vec, time= c(1,2,3,4,5))
## [1] 5 4 4 3 3 3 2 2 2 2 1 1 1 1 1
Create a vector of two random uniform numbers. In a spatial map,
these can be interpreted as x and y coordinates that give the location
of an individual (such as a marked forest tree in a plot that has been
mapped). Using one of R’s inverse trigonometry functions
(asin()
, acos()
, or atan()
),
convert these numbers into polar coordinates
set.seed(1000)
xy_coordinates <- runif(2)
polar_coordinates_r <- sqrt(xy_coordinates[1]+xy_coordinates[2])
print(polar_coordinates_r)
## [1] 1.042461
polar_coordinates_0 <- atan(xy_coordinates[2]/xy_coordinates[1])
print(polar_coordinates_0)
## [1] 1.162948
polar_coordinates <- c(polar_coordinates_r, polar_coordinates_0)
print(polar_coordinates)
## [1] 1.042461 1.162948
Create a vector
queue <- c("sheep", "fox", "owl", "ant")
where queue
represents the animals that are lined up to enter Noah’s Ark, with the
sheep at the front of the line. Using R expressions, update
queue
as:
queue <- c("sheep", "fox", "owl", "ant")
# a. the serpent arrives and gets in line;
queue <- c(queue, "serpent")
print (queue)
## [1] "sheep" "fox" "owl" "ant" "serpent"
# b. the sheep enters the ark;
queue <- queue[-1]
print(queue)
## [1] "fox" "owl" "ant" "serpent"
# c. the donkey arrives and talks his way to the front of the line;
queue <- c("donkey", queue)
print(queue)
## [1] "donkey" "fox" "owl" "ant" "serpent"
# d. the serpent gets impatient and leaves;
queue <- queue[-5]
print(queue)
## [1] "donkey" "fox" "owl" "ant"
# e. the owl gets bored and leaves;
queue <- queue[-3]
print(queue)
## [1] "donkey" "fox" "ant"
# f. the aphid arrives and the ant invites him to cut in line.
queue <- append(queue, "aphid", after=2)
print(queue)
## [1] "donkey" "fox" "aphid" "ant"
# g. Finally, determine the position of the aphid in the line.
which(queue=="aphid")
## [1] 3
Use R to create a vector of all of the integers from 1 to 100 that are not divisible by 2, 3, or 7.
my_vec<- seq(1,100) # making vector sequence 1 to 100
print(my_vec)
## [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
#my_vec <- my_vec[which((my_vec%%2) >0)] # %% gives remainders after dividing, >=1 selecting those with a remainder greater than or equal to 1
#print(my_vec)
my_vec2<- my_vec[which((my_vec%%2)>=1 & (my_vec%%3)>=1 & (my_vec%%7)>=1)]
print(my_vec2)
## [1] 1 5 11 13 17 19 23 25 29 31 37 41 43 47 53 55 59 61 65 67 71 73 79 83 85
## [26] 89 95 97