Data Frame Operations in R

Which function combines data frames row-wise?

• combine()

• rbind()

• addrow()

• cbind()

How do you rename a column?

• df$1 <- 'name'

• colnames(df)[1] <- 'name'

• names(df)[1] <- 'name'

• rename(df, 'name')

What function do you use to bind columns from two data frames?

• rbind()

• cbind()

• merge()

• addcol()

Which code removes the second column from a data frame df?

• df[, -2]

• df[-2, ]

• remove(df, 2)

• drop(df, 2)

How do you view the first few rows of a data frame in R?

• top(df)

• head(df)

• preview(df)

• df[1:5, ]

If df <- df[-1, ], what happens?

• First row removed

• First column removed

• Row added

• Nothing

How do you add a new column to a data frame?

• new<- cbind(df, num=c(1,2,3))

• add(df, 1,2,3)

• merge(df)

• update(df)

Which line will add a new row to data frame df?

• rbind(df, new_row)

• append(df, new_row)

What does str(df) show?

• Number of rows only

• Structure and type of columns

How can you check column names in a data frame?

• colnames(df)

• names(df)

• Both a and b