jupyter notebook / 由于 KeyError 无法启动内核答案

【问题标题】：jupyter notebook / Failed to start the kernel due the KeyErrorjupyter notebook / 由于 KeyError 无法启动内核
【发布时间】：2019-01-30 09:33:05
【问题描述】：

我的 jupyter notebook 无法启动，因为内核死机并出现以下内核错误：

Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/tornado/web.py", line 1512, in _execute
    result = yield result
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/tornado/gen.py", line 1055, in run
    value = future.result()
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/tornado/concurrent.py", line 238, in result
    raise_exc_info(self._exc_info)
  File "<string>", line 4, in raise_exc_info
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/tornado/gen.py", line 1069, in run
    yielded = self.gen.send(value)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/notebook/services/sessions/handlers.py", line 67, in post
    model = yield gen.maybe_future(sm.get_session(path=path))
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/notebook/services/sessions/sessionmanager.py", line 170, in get_session
    return self.row_to_model(row)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/notebook/services/sessions/sessionmanager.py", line 209, in row_to_model
    raise KeyError
KeyError

【问题讨论】：

操作系统？像 Conda 这样的环境还是独立安装？内核也死了，然后无法重新启动或内核从未启动。
macOS，独立安装，内核启动失败，返回：ImportError: cannot import name 'create_prompt_application'

标签： python-3.x pycharm jupyter

【解决方案1】：

就我而言，问题源于jupyter-console 和ipython 中的prompt-toolkit 需求冲突。

您可以使用pip check 来确定您是否有同样的问题。如果输出类似于我下面的输出，则必须修复损坏的包问题。

>>> pip check ipython 
ipython 5.0.0 has requirement prompt-toolkit<2.0.0,>=1.0.3, but you'll have prompt-toolkit 2.0.9 which is incompatible. 

>>> pip check jupyter-console 
jupyter-console 6.0.0 has requirement prompt-toolkit<2.1.0,>=2.0.0, but you'll have prompt-toolkit 1.0.15 which is incompatible.

快速解决方法是尝试最初提到的解决方案here。

pip uninstall prompt-toolkit 
pip install prompt-toolkit==1.0.15 
pip uninstall jupyter-console 
pip install jupyter-console==5.2.0

【讨论】：