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) |
07 | Old: print?????????????
|
08 | New: print()??????????? |
10 | Old: print>>sys.stderr, "fatal error" |
11 | New: print("fatal error", file=sys.stderr) |
14 | New: 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
>>>
出錯原因：
??? python v3.0以后的版本中將v2.x版本的print 改為了print().
?? 所以此處調用print("Hello World!")則可成功。