Question

    #!/usr/bin/python

    password_out = ''
    case_changer = ord('a') - ord('A')
    encryption_key = (('a','m'), ('b','h'), ('c','t'), ('d','f'), ('e','g'),
    ('f','k'), ('g','b'), ('h','p'), ('i','j'), ('j','w'), ('k','e'), ('l','r'),
    ('m','q'), ('n','s'), ('o','l'), ('p','n'), ('q','i'), ('r','u'), ('s','o'),
    ('t','x'), ('u','z'), ('v','y'), ('w','v'), ('x','d'), ('y','c'), ('z','a'))

    #program greeting
    print ('This program will encrypt and decrypt user passwords \n')

    # get selection (encrypt /decrypt)
    which = input('Enter (e) to encrypt a password, and (d) to decrypt :')



     while which != 'e' and which != 'd':
            which = input ("\nINVALID -Enter 'e' to encrypt, 'd' to decrypt:")

        encrypting = (which == 'e') # assigns True or False

        # get password
        password_in = input ('Enter password:')

        #perform encryption / decryption

if encrypting:
    from_index = 0
    to_index = 1
else:
    from_index = 1
    to_index = 0

    case_changer = ord('a') - ord('A')

    for ch in password_in:
        letter_found = False

        for t in encryption_key:
            if ('a' <= ch and ch <= 'z') and ch == t[from_index]:
                password_out = password_out + t[to_index]
                letter_found = True

            elif ('A' <= ch and ch <= 'Z') and chr(ord(ch) + 32) == t[from_index]:
                password_out = password_out + chr(ord(t[to_index]) - case_changer)
                letter_found = True

        if not letter_found:
            password_out = password_out + ch

    # output
    if encrypting:
        print ("Your encrypted password is : ", password_out)
    else:
        print ("Your decrypted password is : ", password_out)

问题：此代码来自“计算机科学入门”一书。我没有完全获得ord（）功能，只有＆＃39; a＆＃39;到＆＃39; A＆＃39;被定义为。它如何从他人中减去价值？我检查了ord（）函数的python文档，但没有完全回答我的问题。

Answer 1

编辑：您应该使用raw_input（）函数来避免Python尝试在输入中计算表达式。

变量未定义错误 - python

1 个答案: