如何在 Python 中打印到 stderr? [英] How to print to stderr in Python?

问题描述

有几种写入标准错误的方法:

# 注意:第一个在 Python 3 中不起作用打印 >>sys.stderr，垃圾邮件"sys.stderr.write("垃圾邮件
")os.write(2, b"垃圾邮件
")从 __future__ 导入 print_function打印(垃圾邮件"，文件=sys.stderr)

这似乎与 zen of Python #13 ^† 相矛盾，那么这里有什么区别?其中一种方式有什么优点或缺点?应该用哪种方式?

^† _{应该有一种——最好只有一种——显而易见的方法.}

解决方案

我发现这是唯一一个简短、灵活、便携和可读的方案:

#这行只有你还关心Python2从 __future__ 导入 print_function导入系统def eprint(*args, **kwargs):打印(*args，文件=sys.stderr，**kwargs)

可选功能eprint 节省了一些重复.它可以像标准的print函数一样使用:

<预><代码>>>>打印(测试")测试>>>eprint(测试")测试>>>eprint("foo", "bar", "baz", sep="---")foo---bar---baz

There are several ways to write to stderr:

# Note: this first one does not work in Python 3
print >> sys.stderr, "spam"

sys.stderr.write("spam
")

os.write(2, b"spam
")

from __future__ import print_function
print("spam", file=sys.stderr)

That seems to contradict zen of Python #13 ^†, so what's the difference here and are there any advantages or disadvantages to one way or the other? Which way should be used?

^† _{There should be one — and preferably only one — obvious way to do it.}

解决方案

I found this to be the only one short, flexible, portable and readable:

# This line only if you still care about Python2
from __future__ import print_function

import sys

def eprint(*args, **kwargs):
    print(*args, file=sys.stderr, **kwargs)

The optional function eprint saves some repetition. It can be used in the same way as the standard print function:

>>> print("Test")
Test
>>> eprint("Test")
Test
>>> eprint("foo", "bar", "baz", sep="---")
foo---bar---baz

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