在 Python2.x 中使用 print()(函数版本) [英] Using print() (the function version) in Python2.x

问题描述

我理解语句和表达式的区别，我理解 Python3 把 print() 变成了一个函数.

I understand the difference between a statement and an expression, and I understand that Python3 turned print() into a function.

然而，我在各种 Python2.x 解释器上运行了一个用括号括起来的 print() 语句并且它运行完美，我什至不需要导入任何模块.

However I ran a print() statement surrounded with parenthesis on various Python2.x interpreters and it ran flawlessly, I didn't even have to import any module.

我的问题:下面的代码 print("Hello SO!") 在 Python2.x 中是作为语句还是表达式计算的?

My question: Is the following code print("Hello SO!") evaluated as a statement or an expression in Python2.x?

推荐答案

考虑以下表达式:

a = ("Hello SO!")
a = "Hello SO!"

它们是等价的.同理，用一个语句:

They're equivalent. In the same way, with a statement:

statement_keyword("foo")
statement_keyword "foo"

也是等价的.

请注意，如果您将打印功能更改为:

Notice that if you change your print function to:

print("Hello","SO!")

您会注意到 python 2 和 python 3 之间的区别.在 python 2 中，(...,...) 被解释为元组，因为 print 是一个语句，而在 python 中3、它是一个带有多个参数的函数调用.

You'll notice a difference between python 2 and python 3. With python 2, the (...,...) is interpteted as a tuple since print is a statement whereas in python 3, it's a function call with multiple arguments.

因此，为了回答手头的问题，print 在 python 2.x 中被评估为语句，除非您 from __future__ import print_function(在 python 2.6 中引入)

Therefore, to answer the question at hand, print is evaluated as a statement in python 2.x unless you from __future__ import print_function (introduced in python 2.6)

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