R Programming Variable Concepts

Which of the following is not an acceptable R variable name?

• min_height

• celsius2kelvin

• _age

• max.height

What will happen if you try to name a variable .mass?

• nothing

• the variable will be named .mass

• .mass will be added to the end of the pre-existing name

• it will create a hidden variable

If you have a variable you want to remove, which command do you use?

• rm

• ls

• list

• remove <- (function.name)

If I type the code

mass <- 47.5

mass <- mass * 2

What value will be associated with the function "mass"?

• 47.5

• 2

• 95

• 2,256.25

mass <- 12

age <- 6

If I type mass > age, what response will I get?

• TRUE

• FALSE

• YES

• NO

What information about the gapminder data can I get from the command

ls -lh data/gapminder_data.csv

• how many lines of data there are

• a table showing the data

• the file size

What will be the outcome of the following command?

?write.table

• It will provide an information page about the command

• It will tell you the location of your table

• It will create a table with the data you provided

When trying to determine the vector type, which of the following elements would not be called characters?

• c(1, 2, 'K')

• c('d', 'e', 'f')

• c(1, 2, 3)

Answer explanation

c(1, 2, 3) is considered numeric.

What will be the outcome of the following code?

paste(c("a", "b"), "c", sep = ","

• "a,c" "b,c"

• "a c|b c"

• "a", "b", "c"

What will be the result of the following code?

paste(c( "a", "b"), "c", collapse = "|"

• "a"|"b"|"c"

• "a,c|b,c"

• "a", "b", "c"