I keep getting ERROR (str' object has no attribute 'append')

Question

I get ERROR (str' object has no attribute 'append')<\/code> in line (encoded_text.append("new_letter"))<\/code> but not in (encoded_text.append("x"))<\/code> although encoded_text<\/code> is defined as a List<\/code> type.

alphabet = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z']

direction = input("Type 'encode' to encrypt, type 'decode' to decrypt:\n")
text = input("Type your message:\n").lower()
shift = int(input("Type the shift number:\n"))

text = list(text)
encoded_text = []
encoded_text.append("x") 

if(direction == "encode"):
  for x in text:
    new_index = alphabet.index(x) + shift
    if(new_index > len(alphabet)):
      new_index = new_index - len(alphabet)

    new_letter = alphabet[new_index]
    encoded_text.append(new_letter) 
    encoded_text= "".join(encoded_text)

  print(f"The encoded text is {encoded_text}.")

Answer 1

Two problems: incorrect alignment and unnecessary quotes:

alphabet = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z']

direction = input("Type 'encode' to encrypt, type 'decode' to decrypt:\n")
text = input("Type your message:\n").lower()
shift = int(input("Type the shift number:\n"))

text = list(text)
encoded_text = []
encoded_text.append("x") 

if(direction == "encode"):
  for x in text:
    new_index = alphabet.index(x) + shift
    if(new_index > len(alphabet)):
      new_index = new_index - len(alphabet)

    new_letter = alphabet[new_index]
    encoded_text.append(new_letter)            # << removed quotes here
  encoded_text= "".join(encoded_text)          # << corrected alighment here

  print(f"The encoded text is {encoded_text}.")