Simple tips to write efficient code

Programming CPU heavy data processing and analysis tasks? Some of my clients are amazed by the execution speed of my code, and I am not a professional software developer! Nevertheless, here are some of my simple tricks to keep in mind when writing code in any language:

• Do calculations only once: avoid repeating the same arithmetic, try to store results in memory and reuse them later (yes more management!)
• Watch loops contents… if it contains repetitive inefficient code, this code is triggered many times!
• Example of inefficient code inside a loop: if/else and switch statements to process user options. Process options outside the loop and write several variants of the loop!
• Avoid writing a ton of 1- or 2-lines functions just to make things “cute”. Call stack can become heavy and slow in the computer
• Use the built-in language features, for example the vectorized operations in R, Matlab or Python, or the native functions in VBA and JavaScript (they will always be faster than your own implementation)
• With object-oriented languages: write classes! Code is always cleaner and simpler to debug.
• Having a code profiler? Profile execution and work on most time-consuming steps.

Again, these are just some of the things I keep in mind when I code something… But it helps a lot!