Is it true that this is a factor?
factor(c(1,2,3,4,5,6,7,8))
Yes
because it is a vector of eight values passed as an argument to the function factor.
Is it true that this is a factor?
factor(1,2,3,4,5,6,7,8)
No
because it is eight values passed as eight arguments to the function factor.
How many levels are in factor f where
f <- factor(c(1,1,2,1,3,4,3,5,1))
Five
because there are five unique values in factor f.
What is levels(f) where
f <- factor(c(1,1,2,1,3,4,3,5,1))
[1] "1" "2" "3" "4" "5"
because levels() gets a list of factors.
What is levels(f) where
f <- factor(c(1,3,4,4), levels=c(1,2,3,4))
[1] "1" "2" "3" "4"
because a factor can have levels not represented in the data.
What is f where
f <- factor(c(1,3,4,4,5), levels=c(1,2,3,4))
[1] 1 3 4 4 <NA>
because a factor cannot have data not represented in the levels.
What is f where
f <- factor(c("sunny", "cloudy", "rainy", "cloudy"), levels=c("sunny", "cloudy", "windy", "rainy"))
[1] 1 3 4 4 <NA>
because a factor cannot have data not represented in the levels.
How many levels does f have where f is
f <- factor(1:6)
six
because 1:6 produces a vector of values 1 through 6.
How many levels does f have where f is
f <- factor(1:6,1:9)
nine
because the second argument to factor() is levels and 1:9 produces a vector of values 1 through 9.
Is it true that this is an array?
array(1:8, dim=c(8))
yes
because it is a collection of values with one dimension.
Is it true that this is an array?
array(1:8, dim=c(2,4))
yes
because it is a collection of values with two dimensions.
What is class(a) where
a <- array(1:8, dim=c(2,4))
matrix
because R treats two-dimensional arrays and matrices the same, and uses matrix to refer to both.
Is it true that this is an array?
array(1:8, dim=c(2,2,2))
yes
because it is a collection of values with three dimensions.
Is it true that this is an array?
array(1:3, dim=c(2,4,2))
yes
because the data used will be recycled to fit the dimensions.
Is it true that this is an array?
array(1:6, dim=c(2,2,2), dimnames=c("rows","columns","groups")
no
because dimnames must be a list.
Is it true that this is an array?
array(1:6, dim=c(2,2,2), dimnames=list("rows","columns","groups")
no
because dimnames does not have a value for each component of each dimension.
Is it true that this is an array?
array(1:6, dim=c(2,2,2), dimnames=list(c("row1","row2"),c("col1","col2"),c("group1","group2")))
yes
because dimnames has a value for each component of each dimension.