python 2.7 TypeError：一元+的错误操作数类型：'str'
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python 2.7 TypeError: bad operand type for unary +: 'str'
提问by Marco Dinatsoli
this is my code
这是我的代码
message = "From: %s\r\n" % fromaddr
+ "To: %s\r\n" % toaddrs
+ "CC: %s\r\n" % ",".join(cc)
+ "Subject: %s\r\n" % message_subject
+ "\r\n"
+ msg
i am getting this error:
我收到此错误：
+ "To: %s\r\n" % toaddrs
TypeError: bad operand type for unary +: 'str'
may you help please
你能帮忙吗
采纳答案by Matthew Drury
To fix your problem, wrap the whole expression for message in parenthesies:
要解决您的问题，请将 message 的整个表达式用括号括起来：
message = (
"From: %s\r\n" % fromaddr
+ "To: %s\r\n" % toaddrs
+ "CC: %s\r\n" % ",".join(cc)
+ "Subject: %s\r\n" % message_subject
+ "\r\n"
+ msg
)
The error message python is giving is quite helpful. Unary operations are those with exactly one argument. + can be used as a unary operation in python,
python 给出的错误消息非常有帮助。一元运算是那些只有一个参数的运算。+ 可以用作python中的一元运算，
x = + 2
is valid code. What's happening in your snippet is that the first line:
是有效代码。您的代码段中发生的事情是第一行：
message = "From: %s\r\n" % fromaddr
is being interpreted as a full assignment statement. The next line starts a new statement, but is incomplete.
被解释为完整的赋值语句。下一行开始一个新的语句，但不完整。
