在python中使用print（）时，raw write（）返回无效的长度：OSError: raw write() returned invalid length 254 (should have been between 0 and 127)

写出一个不是code的bug,很烦恼，解决了挺长时间，都翻到外文来看，不过还是解决了，只尝试了一种简单可观的方法，希望对大家有用

我正在使用Django与Keras(tensorflow)来训练一个模型来识别python中的图像。在python中使用print（）时，raw write（）返回无效的长度，

即使我想把print()注释掉，也时不时的蹦出来,错误如下：

Traceback (most recent call last):
  File "D:\AI\Python35\lib\site-packages\django\core\handlers\exception.py", line 35, in inner
    response = get_response(request)
  File "D:\AI\Python35\lib\site-packages\django\core\handlers\base.py", line 128, in _get_response
    response = self.process_exception_by_middleware(e, request)
  File "D:\AI\Python35\lib\site-packages\django\core\handlers\base.py", line 126, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "E:\PyCharmWork\PythonWebApp\ApiPicDjangoSite\PicWeb\views.py", line 94, in trainPic
    bankTrain.Cnn_bank_run(lineData,linefile)
  File "E:\PyCharmWork\PythonWebApp\ApiPicDjangoSite\PicWeb\Cnn_Bank_train.py", line 70, in Cnn_bank_run
    modelTrain.modelTrain_ByType(kwargs[1],X_train,Y_train,X_test,Y_test)
  File "E:\PyCharmWork\PythonWebApp\ApiPicDjangoSite\PicWeb\trainModel_init.py", line 113, in modelTrain_ByType
    verbose=1, validation_data=(kwgs[3], kwgs[4]))
  File "D:\AI\Python35\lib\site-packages\keras\models.py", line 960, in fit
    validation_steps=validation_steps)
  File "D:\AI\Python35\lib\site-packages\keras\engine\training.py", line 1650, in fit
    validation_steps=validation_steps)
  File "D:\AI\Python35\lib\site-packages\keras\engine\training.py", line 1233, in _fit_loop
    callbacks.on_epoch_end(epoch, epoch_logs)
  File "D:\AI\Python35\lib\site-packages\keras\callbacks.py", line 73, in on_epoch_end
    callback.on_epoch_end(epoch, logs)
  File "D:\AI\Python35\lib\site-packages\keras\callbacks.py", line 306, in on_epoch_end
    self.progbar.update(self.seen, self.log_values, force=True)
  File "D:\AI\Python35\lib\site-packages\keras\utils\generic_utils.py", line 369, in update
    sys.stdout.write(info)
OSError: raw write() returned invalid length 254 (should have been between 0 and 127)

错误都很有规律可循：
Error like this：
OSError: raw write() returned invalid length 318 (should have been between 0 and 159)
OSError: raw write() returned invalid length 8 (should have been between 0 and 4)
OSError: raw write() returned invalid length 130(should have been between 0 and 65)
Please note： 318=159x2 8=4x2 130=65x2

原因：可能与最近的Windows 10更新有关。我有版本1709（操作系统版本16299.64）,

　　我认为这可能是unicode字符的返回值（正常长度的两倍）？

　　我实际上可以在外部powershell.exe中重现此错误，所以这本身不是Code相关的。

　　总的来说，与win10系统、版本有关系，踩中雷区了（本人win10,版本    10.0.16299 版本 16299）

　　可以cmd一下,输入msinfo32，就能看到版本情况

 

解决方案：写入以下代码到报错提示的python的中，写在开头

事先要看你是否pip  win_unicode_console,没有，就赶快动手

import win_unicode_console
win_unicode_console.enable()

 如下：

 

参考：https://github.com/Microsoft/vscode/issues/39149

https://qiita.com/non0/items/4014b81f5a2d232ae22f

https://stackoverflow.com/questions/47356993/oserror-raw-write-returned-invalid-length-when-using-print-in-python