Why is iPython notebook interpreting commented out lines?

Question

This question is not about a specific error---the error arrises because I'm using matplotlib's tight_layout incorrectly.

I want to know why iPython is interpreting a line of code that I have commented out--or, rather, under what circumstances this is expected to happen (i.e., I need to relaunch the kernel, or whatever).

The error seems to persist, in spite of the fact that I re-executed the relevant imports.

Code:

import forecasting_report.analyze as fcst_rprt
analysis = fcst_rprt.ForecastingReport()
analysis.analyze()
results = analysis.user_dict

Error says:

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-6-a62e6e8717be> in <module>()
      1 analysis = fcst_rprt.ForecastingReport()
----> 2 analysis.analyze()
      3 results = analysis.user_dict

/Users/[...]/ForecastingReport/forecasting_report/analyze.py in analyze(self)  
     44         self.breakdown = help.breakdown(self.user_dict)
---> 45         #plots.plot_breakdown(self.breakdown, self.path)
     46 
     47     def write_results(self):

<Error Stack continues>

Note:

A perfectly fine answer is : "That's just not the way it works". To be sure, I haven't tried to reproduce this error at the command line, so it just may be my ignorance of the Python interpreter.

Yes--that seems to fix the problem. I just don't know why the `import` statement doesn't pick up changes to the module. — BenDundee, May 03 '13 at 16:12
in the past, i've noticed that if I installed a module, it wouldn't automatically become available, a restart is needed. — babalu, May 03 '13 at 16:14
Python will only import a module once, if you need to reload it somewhere, you can use: `reload(module_name)` — Dave Challis, May 03 '13 at 16:14
@babalu: is this true in the interpreter as well? Or just the notebook? — BenDundee, May 03 '13 at 16:14
@DaveChallis: So simply re-issuing the `import` statement is not enough? — BenDundee, May 03 '13 at 16:16
Yup, I believe python will see that the module has already been imported, and do nothing, regardless of whether the module has been modified since. — Dave Challis, May 03 '13 at 16:17
@DaveChallis: Why don't you post that as an answer. Please :) — BenDundee, May 03 '13 at 16:18

score 1 · Accepted Answer · answered May 03 '13 at 20:44

Python will only initialise an imported module once, further calls to import will have no effect, even if the module has been modified since being read.

To reload a module, use the builtin function reload on the already imported module object, e.g.:

import mymodule

# ...later...
reload(mymodule)

score 1 · Answer 2 · edited May 23 '17 at 12:04

1

try

%load_ext autoreload
%autoreload 2

which should work with ipython terminal, i not sure if it works in ipython notebook. You can view help through autoreload? and this post: Autoreload of modules in IPython

edited May 23 '17 at 12:04

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answered May 03 '13 at 20:48

Shijing Lv

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Why is iPython notebook interpreting commented out lines?

2 Answers2