27. String reversal

Use string indexing to reverse a string, not a for loop or for-comprehension.

27.1. Don’t do this

name = 'one-off coder'
name = ''.join([name[i] for i in range(len(name) - 1, -1, -1)])

27.2. Do this

Use slicing to reverse a string. The first number is the start index, the second number is the stop index and the last number is the skip. Since we are starting and stopping at the start and stop index, those values are omitted. The skip is -1 which forces the skip to go backwards.

name = 'one-off coder'
name = name[::-1]

We can also print just even-indexed characters backwards.

name = 'one-off coder'
name = name[0::2][::-1]

We can also print just odd-indexed characters backwards.

name = 'one-off coder'
name = name[1::2][::-1]