python - 类型错误 : unsupported operand type(s) for &: 'NoneType' and 'str'

Question

我在为学校作业创建字符打印机时遇到了一些问题，尽管在 StackOverflow 上到处查看，但我不知道如何解决它。我正在尝试使用户能够为前两个顶行和底行输入他们想要的符号，并根据字长将他们的两个文本以正斜杠和反斜杠居中。然而，这已被证明是一个问题。

我尝试过更改变量以及创建将文本长度封装为整数的变量，这被证明是不成功的。

Repeats = input("How many times should the symbol repeat (1-30 CHARACTERS)?:")
insertText = input("Please enter text:")
insertText = str(insertText)
insertMoreText =input("Please enter text (again):")
insertMoreText= str(insertMoreText)
Repeats = int(Repeats)

#Determining text lengths/stored variables:
text1length = len(insertText)
text2length = len(insertMoreText)
forwardSlash = str("/")
backSlash = str("\\")
symbolsbeforeText = "*"
if(Repeats <= 30):
    print(firstSymbol * Repeats)
    print(secondSymbol * Repeats)
    print(symbolsbeforeText * Repeats)
    print (forwardSlash * text1length) & (insertText.upper()) & (forwardSlash 
    * text1length)
    print (backSlash * text2length) + (insertMoreText.lower()) + (backSlash * 
    text2length)
    print(symbolsbeforeText * Repeats)
    print(secondSymbol * Repeats)
    print(firstSymbol * Repeats)    
else:
    print("You have reached the repetition threshold, please try again.")

错误:

Traceback (most recent call last):
 File "C:\Users\colby\trainingTime.py", line 28, in <module>
 print (forwardSlash * text1length) & (insertText.upper()) & 
 (forwardSlash * text1length)
 TypeError: unsupported operand type(s) for &: 'NoneType' and 'str'

Process terminated with an exit code of 1

Answer 1

print 函数始终返回 None，并且您正在对 print 和 的返回值执行按位与运算(insertText.upper())，这是一个字符串，导致上述错误。

您应该调用 print 并将整个表达式括在括号中作为参数:

print((forwardSlash * text1length) & (insertText.upper()) & (forwardSlash * text1length))
print((backSlash * text2length) + (insertMoreText.lower()) + (backSlash * text2length))