Data frames and matrices - column selection
All values in a matrix must have the same data type, which has efficiency implications when selecting rows and columns.
Suppose we have two objects, mat (a matrix) and df (a data frame).
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Writing Efficient R Code
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Using the microbenchmark() function, how long does it take to select the first column from each of these object? In other words, which is faster mat[, 1] or df[, 1]?
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# Which is faster, mat[, 1] or df[, 1]?
microbenchmark(___, ___)