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Variable not recognized in nested or filtered list comprehension under IPython.embed()

See original GitHub issue

If I run IPython.embed() and then try to execute the following code from the command line, I get a NameError. Variables defined in the local namespace seem to become invisible when there is a nested list comprehension. They are visible for a single-level list comprehension, but I get a NameError if I refer to a variable from a second or deeper level.

This does not happen with a normal IPython shell or when I use IPython.start_ipython().

Here is the code to reproduce the error.

In [1]: x = [1, 2, 3]                                                                                                                                                                            
In [2]: [i for i in x]                                                                                                                                                                           
Out[2]: [1, 2, 3]  # fine

In [3]: [i for i in x for j in x]                                                                                                                                                                
---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
<ipython-input-2-ebe839e86c71> in <module>
----> 1 [i for i in x for j in x]

<ipython-input-2-ebe839e86c71> in <listcomp>(.0)
----> 1 [i for i in x for j in x]

NameError: name 'x' is not defined

In [4]: y = [4, 5, 6]                                                                                                                                                                            
In [5]: [i for i in x for j in y]                                                                                                                                                                
---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
<ipython-input-5-ba9a21c5a38c> in <module>
----> 1 [i for i in x for j in y]

<ipython-input-5-ba9a21c5a38c> in <listcomp>(.0)
----> 1 [i for i in x for j in y]

NameError: name 'y' is not defined

This is in IPython 7.9.0 with Python 3.7.3.

Issue Analytics

State:
Created 4 years ago
Reactions:1
Comments:9 (2 by maintainers)

Top GitHub Comments

2reactions

tciescommented, Feb 27, 2022

Same, I love IPython, I love IPython.embed(), and this issue makes it significantly less practical to work with 😢 .

2reactions

congvmitcommented, Feb 18, 2022

I am facing this problems while debugging my code. Any updates?

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