Caesar Cipher

Shift every lowercase letter in "hello world" forward by 3 (wrapping z→c), keep spaces, and print the result.

khoor zruog

chr((ord(ch) - ord('a') + shift) % 26 + ord('a')) for letters; keep spaces as-is.

message = "hello world"
shift = 3
result = ""
for ch in message:
    if ch == " ":
        result += ch
    else:
        result += chr((ord(ch) - ord("a") + shift) % 26 + ord("a"))
print(result)

Run your code to check it…