print SyntaxError: invalid syntax错误的问题

print SyntaxError: invalid syntax错误的问题

2010-05-10 15:19

Print Is A Function

The print statement has been replaced with a print() function, with keyword arguments to replace most of the special syntax of the old print statement (PEP 3105). Examples:

01 Old: print"The answer is", 2*2
02 New: print("The answer is", 2*2)
03
04 Old: printx,           # Trailing comma suppresses newline
05 New: print(x, end=" ") # Appends a space instead of a newline
06
07 Old: print              # Prints a newline
08 New: print()            # You must call the function!
09
10 Old: print>>sys.stderr, "fatal error"
11 New: print("fatal error", file=sys.stderr)
12
13 Old: print(x, y)       # prints repr((x, y))
14 New: print((x, y))      # Not the same as print(x, y)!

You can also customize the separator between items, e.g.:

1 print("There are <", 2**32, "> possibilities!", sep="")

which produces:

There are <4294967296> possibilities!

Note:

* The print() function doesn’t support the “softspace” feature of the old print statement. For example, in Python 2.x, print "A\n", "B" would write "A\nB\n"; but in Python 3.0, print("A\n", "B") writes "A\n B\n".
* Initially, you’ll be finding yourself typing the old print x a lot in interactive mode. Time to retrain your fingers to type print(x) instead!
* When using the 2to3 source-to-source conversion tool, all print statements are automatically converted to print() function calls, so this is mostly a non-issue for larger projects.

操作如下：

										
      
      
      
      

												
       
       
       
       >>>
												
       
       
       
        
												
       
       
       
       print
												
       
       
       
        
												
       
       
       
       "
												
       
       
       
       Hello World!
												
       
       
       
       "
												
       
       
       
        
File 
												
       
       
       
       "
												
       
       
       
       <stdin>
												
       
       
       
       "
												
       
       
       
       , line 
												
       
       
       
       1
												
       
       
       
        
 
												
       
       
       
       print
												
       
       
       
        
												
       
       
       
       "
												
       
       
       
       Hello World!
												
       
       
       
       "
												
       
       
       
        
 
												
       
       
       
       ^
												
       
       
       
        
SyntaxError: invalid syntax

												
       
       
       
       >>>
												
       
       
       
        
 
										
      
      
      
      
								

出错原因：

    python v3.0以后的版本中将v2.x版本的print 改为了print().

   所以此处调用print("Hello World!")则可成功。