Newbie Programming Mistakes

Weird Syntax

comparison to true or false

If you have a bool, you can just use it instead of comparing to true or false:

# some code which produces a bool b
b = a > 5
# return b == false
return not b

Similarly, you don't need to do:

# Unnecessary
if not b:
  return true
else:
  return false

Not using vectorization

If you're using a language like Python or R, you can take advantage of faster SIMD instructions by using vectorized code.
Instead of writing:

a = np.arange(5)
b = np.arange(5)
# Bad
c = np.zeros(5)
for i in range(len(a)):
  c[i] = a[i] + 5*b[i]
# Good
c = a + 5*b