Jupyter Notebook，NameError:未定义，%% time阻止分配 [英] Jupyter Notebook, NameError: is not defined, %%time prevents assignment

问题描述

我在运行Jupyter Notebook(IPython:7.4.0)时遇到一个非常奇怪的错误，该错误未正常分配变量.我花了很多时间来找出原因，徒劳地寻找，变量范围，类型转换和TensorFlow的复杂性;(

I came across a very strange bug running a Jupyter Notebook (IPython: 7.4.0) where a variable was not assigned as normally. It took me quite bit of time to figure out the cause, searching in vain all over, variable scope, type conversion and TensorFlow intricacies ;(

事实上，使用%% time单元格魔术可以防止在单元格中分配变量.因此，在下面的单元格中未定义分配的变量，从而给出了典型的错误消息:未定义NameError:'xxx'."

In fact, using %%time cell magic was preventing assignment of the variable in the cell. Therefore the assigned variable was not defined in the cell below giving a characteristic error message: "NameError: 'xxx' is not defined."

这似乎是已知问题，希望可以对其他人有所帮助.

It seems to be a known issue, hoping that can help someone else.

推荐答案

解决方案很简单，只需从单元格中删除%% time.

The solution is simple, just remove %%time from the cell.

而是使用:

from timeit import default_timer as timer
from datetime import timedelta

start = timer()

# Process
# ...


end = timer()
print ("Execution time HH:MM:SS:",timedelta(seconds=end-start))

来源: Stackoverflow-测量Python中经过的时间?

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