Python 的print报错SyntaxError: invalid syntax

1、

1 #!/usr/bin/python
2 print "hello world!"

print报错：SyntaxError: Missing parentheses in call to 'print'

将打印字符加括号后不报错

1 #!/usr/bin/python
2 print("hello world!")

2、print type

1 #!/usr/bin/python
2 a = "smg"
3 print type(a)

type报错：

print type(a)

^

SyntaxError: invalid syntax

type函数括号后不报错

1 #!/usr/bin/python
2 a = "smg"
3 print( type(a) )

运行结果是：<class 'str'>