Caesar cipher
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Python Basics · Functions →
Caesar cipher
The Roman historian Suetonius wrote that Julius Caesar hid his messages by shifting each letter three places along the alphabet.
alphabet.index(ch) gives a letter's position, from 0 for a to 25 for z. Add the shift and use % 26, so that position 26 wraps back to 0. To decode a message, shift it again by 26 minus the original shift.
Write caesar(text, shift) that moves every lowercase letter shift places along the alphabet, wrapping from z back to a. Leave every other character as it is. caesar("hello, world", 3) is "khoor, zruog".
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