将函数输出输出分配给python中的变量 [英] Assign a function output prints to a variable in python

问题描述

我有一个函数(在某些项目中)，它会打印结果.当我从命令行或另一个python项目中调用它时，它会在终端上打印输出.但我想将所有打印结果存储在一个变量中，如下所示:

I have a function (in some project) that it prints the result.when I call it from the command line or in another python project, it prints the output on the terminal. But I want to store all the print result in a variable, something like this:

output = function_name(function_args)

，而不是将结果打印在终端上，我想将它们存储在output变量中. 同样，main函数返回一些结果(只是一个数字作为状态)，结果我不想那个数字.

and instead of printing the results on the terminal I want to store them in the output variable. also, the main function returns something(just a number as the status) as the result which i do not want that number.

推荐答案

您可以通过重新绑定sys.stdout来做到这一点:

You can do this by rebinding sys.stdout:

>>> def foo():
...     print('potato')
... 
>>> import sys, io
>>> sys.stdout = io.StringIO()
>>> foo()
>>> val = sys.stdout.getvalue()
>>> sys.stdout = sys.__stdout__  # restores original stdout
>>> print(val)
potato

要获得更好的方法，请考虑编写上下文管理器.如果您使用的是Python 3.4+，则已经为您编写了.

For a nicer way to do it, consider writing a context manager. If you're on Python 3.4+, it's already been written for you.

>>> from contextlib import redirect_stdout
>>> f = io.StringIO()
>>> with redirect_stdout(f):
...     foo()
... 
>>> print(f.getvalue())
potato

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