A very common problem with severe performance consequences is the ‘copy-and-append’ pattern. Save me from this craziness, and document that even the simple example below scales terribly. Do this in three steps. (1) Write a for-loop but pre-allocate the result vector and fill it in. (2) Use an sapply() to avoid thinking about pre-allocation. (3) implement the obvious vectorization.
a scalar (length 1) numeric non-negative vector indicating the number of a number will be
identical() that each solution returns the same
result for each implementation.
Verify the inefficiency of copy-and-append using microbenchmark to
evaluate the original function with different values of
and plotting the result.
Verify the performance gain for a single value of
the three implementations.
Find one StackOverflow question where the solution to a significant performance bottleneck is to avoid copy-and-append.
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