为什么这个变量在Python中没有定义？

-4

我一直在试图制作一个python摩斯密码翻译器，并将其复杂化，我想继续沿用我为摩尔斯电码翻译器开发的路径，但是我遇到了一个问题。为什么这个变量在Python中没有定义？

Traceback (most recent call last): 
    File "python", line 114, in <module> 
NameError: name 'firstletter' is not defined

我找不出为什么这个变量没有被定义。下面的代码

wordinput = input("What do you want to convert") 
word = str(wordinput.upper) 

if word[0] == 'A': 
    firstletter = ".-" 
elif word[0] == "B": 
    firstletter = "-..." 
elif word[0] == 'C': 
    firstletter = '-.-.' 
elif word[0] == 'D': 
    firstletter = '-..' 
elif word[0] == 'E': 
    firstletter = '.' 
elif word[0] == 'F': 
    firstletter = '..-.' 
elif word[0] == 'G': 
    firstletter = '--.' 
elif word[0] == "H": 
    firstletter = '....' 
elif word[0] == "I": 
    firstletter = '..' 
elif word[0] == 'J': 
    firstletter = ".." 
elif word[0] == 'K': 
    firstletter = '-.-' 
elif word[0] == 'L': 
    firstletter = '.-..' 
elif word[0] == 'M': 
    firstletter = '--' 
elif word[0] == 'N': 
    firstletter = '-.' 
elif word[0] == 'O': 
    firstletter = '---' 
elif word[0] == 'P': 
    firstletter = '.--.' 
elif word[0] == 'Q': 
    firstletter = '--.-' 
elif word[0] == 'R': 
    firstletter = '.-.' 
elif word[0] == 'S': 
    firstletter = '...' 
elif word[0] == 'T': 
    firstletter = '-' 
elif word[0] == 'U': 
    firstletter = '..-' 
elif word[0] == 'V': 
    firstletter = '...-' 
elif word[0] == 'W': 
    firstletter = '.--' 
elif word[0] == 'X': 
    firstletter = '-..-' 
elif word[0] == 'Y': 
    firstletter = '-.--' 
elif word[0] == 'Z': 
    firstletter = '--..' 

if word[1] == 'A': 
    secondletter = ".-" 
elif word[1] == "B": 
    secondletter = "-..." 
elif word[1] == 'C': 
    secondletter = '-.-.' 
elif word[1] == 'D': 
    secondletter = '-..' 
elif word[1] == 'E': 
    secondletter = '.' 
elif word[1] == 'F': 
    secondletter = '..-.' 
elif word[1] == 'G': 
    secondletter = '--.' 
elif word[1] == "H": 
    secondletter = '....' 
elif word[1] == "I": 
    secondletter = '..' 
elif word[1] == 'J': 
    secondletter = ".." 
elif word[1] == 'K': 
    secondletter = '-.-' 
elif word[1] == 'L': 
    secondletter = '.-..' 
elif word[1] == 'M': 
    secondletter = '--' 
elif word[1] == 'N': 
    secondletter = '-.' 
elif word[1] == 'O': 
    secondletter = '---' 
elif word[1] == 'P': 
    secondletter = '.--.' 
elif word[1] == 'Q': 
    secondletter = '--.-' 
elif word[1] == 'R': 
    secondletter = '.-.' 
elif word[1] == 'S': 
    secondletter = '...' 
elif word[1] == 'T': 
    secondletter = '-' 
elif word[1] == 'U': 
    secondletter = '..-' 
elif word[1] == 'V': 
    secondletter = '...-' 
elif word[1] == 'W': 
    secondletter = '.--' 
elif word[1] == 'X': 
    secondletter = '-..-' 
elif word[1] == 'Y': 
    secondletter = '-.--' 
elif word[1] == 'Z': 
    secondletter = '--..' 





print(firstletter + secondletter) 
import os 
os.system("pause")

来源

2017-01-06 Jacob grose

好主啊，用字典！和一个循环！ – kindall

不确定所有执行的代码都会*创建*（提示）该变量。 – usr2564301

这伤害了我的眼睛。使用字典！ – dawg

你的问题是与分配：

word = str(wordinput.upper)

您未能通话功能上;相反，您将功能描述符分配给字。当转换描述符的字符串，字值

"<built-in method upper of str object at 0x7f377ea143e8>"

因此，无论输入的，你想转换“<”和“b”;第一个没有覆盖你的列表，所以你的程序崩溃。

更改行来调用例程：

word = str(wordinput.upper())

下一步工作

The problem will still occur if the user enters any input other than pure letters. Add a line before your long **if** to give a default value, whatever you'd like to see printed if the input isn't a letter. I use a space here: 

firstletter = ' '

的改进

使用参考词典：

code = { 'A': ".-", 'B': "-...", etc. 
     }

的添加了一个循环来通过串并转换单个字母：

for c in word: 
    if c in code: 
     morse_char = code[c] 
    else: 
     morse_char = ' ' 
    print(morse_char)

这是否保存您的手指肌肉？

来源

2017-01-06 23:49:04 Prune

大写字母已经是一个字符串了，不是吗？ – Li357

只用'upper'修复，我仍然得到'NameError：name'首字母未定义'（对于不在OP列表中的所有输入）。解决方案是（仍然）在可怕的“if”之前定义“firstletter”。我看到你提出了一个更好的解决方案 - 但最好指出为什么OP首先得到这个错误。 – usr2564301

我不明白这个问题;该行直接从我的工作示例中粘贴，这是唯一的变化。你输入了纯alpha输入吗？如果没有，那么你*仍然会得到我在文中所述的错误。 – Prune

我同意，我有两个小技巧为你第一：定义firstletter和第二个字母上面的if语句或第二

使用for循环转换像下面

wordinput = input("") 
word = str(wordinput.upper) 

for letter in range(0,len(word)+1): 
    if word[letter] == A: 
     convertedword.append(.-) 
... 
... 
...

来源

2017-01-07 00:20:58

为什么这个变量在Python中没有定义？

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