arr = [1, 5, 10, 20]
print(*map(lambda num: num * 2, arr))

arr = [1, 5, 10, 20]
print([num * 2 for num in arr])

Use more consistent example for map
Use more consistent example for map

There is a `map` function in pythin, but for simple single expression
calculations, list comprehensions are much better suited.

While map works well if there is a function, you can pass.
