如何在Python中连接一个固定的字符串和一个变量

Question

我想在主题中包含文件名'main.txt'，以便通过命令行传递文件名。但这样做

python sample.py main.txt #running python with argument 

msg['Subject'] = "Auto Hella Restart Report "sys.argv[1] #line where i am using that passed argument 

Answer 1

我猜你的意思是这样做收到错误：

msg['Subject'] = "Auto Hella Restart Report " + sys.argv[1] 
# To concatenate strings in python, use  ^

Answer 2

试试看

msg['Subject'] = "Auto Hella Restart Report " + sys.argv[1] 

+运算符在Python来连接字符串覆盖。

Answer 3

如果您需要添加两个字符串，你必须使用“+”操作符

因此

msg['Subject'] = your string + sys.argv[1] 

，你也必须在开始时导入SYS

为

import sys 

msg['Subject'] = "Auto Hella Restart Report " + sys.argv[1] 

Answer 4

variable=" Hello..." 
print (variable) 
print("This is the Test File "+variable) 

整数类型...

variable=" 10" 
print (variable) 
print("This is the Test File "+str(variable))