Javascript error ipython is not defined

I can't find any clear documentation if JS / IPython is supported with Jupyterlab, or not. I've installed that extension: jupyter labextension install @jupyter-widgets/jupyterlab-manager ju...

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thomasd3 opened this issue

Jan 2, 2020

· 9 comments

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@thomasd3

I can’t find any clear documentation if JS / IPython is supported with Jupyterlab, or not.

I’ve installed that extension:
jupyter labextension install @jupyter-widgets/jupyterlab-manager
jupyter labextension install jupyter-matplotlib

But when I’m using Backtrader (which uses Bokeh), I get the error in the title.
The same notebook in jupyter notebook works perfectly.

@agoose77

JupyterLab uses Javascript, and IPython is still supported, but the JS API is different. It is likely that if Backtrader was written for Jupyter Notebook, it will not work directly on JupyterLab. It’s not that hard to get extensions working in JupyterLab — you just have to write your own extension to facilitate it.

@glass-ships

Ran into this myself recently when a bit of test code started using the %matplotlib interactive call.
This StackOverflow post seems to indicate that it’s possible, but requires a little extra setup ahead of time.

For example, this extension turns matplotlib objects into interactive widgets.

But the part I think maybe you’re maybe interested in is: conda install nodejs

@thomasd3

I have nodejs on my machine but I didn’t know the ipympl extension, I will try it. thanks!

@sandboiii

I’ve spent entire evening trying to solve this problem, so I came up with this code:

cerebro.run()

%matplotlib widget
cerebro.plot(iplot=False)

This way I managed to display plot in JupyterLab

@sandboiii

using %matplotlib inline should also work

@nickk

I’ve spent entire evening trying to solve this problem, so I came up with this code:

cerebro.run()

%matplotlib widget
cerebro.plot(iplot=False)

This way I managed to display plot in JupyterLab

Thank you, this worked!

@songhuazhang

I’ve spent entire evening trying to solve this problem, so I came up with this code:

cerebro.run()

%matplotlib widget
cerebro.plot(iplot=False)

This way I managed to display plot in JupyterLab

this saved my day!

@MohamedNedal

Excuse me, I’m getting this error:
NameError: name 'cerebro' is not defined

@agoose77

@MohamedNedal are you using cerebro? What are you trying to do?

NameError means you have a name in your code that isn’t defined, e.g. if you run this in the Python interpreter:

It will raise a NameError, because you’ve not defined some_name yet.

Introduction

When working with an application within the browser, there might be a need for some JavaScript environment configurations. Applications such as JupyterLab are one of such applications that need JavaScript support, especially when running interactive code or plots.

In situations where the right environment is not set up in JupyterLab leading to errors. One such error is the Javascript Error: IPython is not defined error message.

In this article, we will discuss how to deal with the JavaScript Error message involving IPython.

Use matplotlib inline to solve JavaScript Error in IPython

In a situation where you are running a plot (using matplotlib) in a JupyterLab environment and encounter a Javascript Error: IPython is not defined error message, you can configure your matplotlib to use the inline magic command which allows you to draw only static plots within your JupyterLab.

To make use of the inline magic command, you can add the statement below before your plot code.

%matplotlib inline

However, this means that you won’t be able to have an interactive plot within your JupyterLab. If you need an interactive plot, the ipympl package is helpful.

ALSO READ: Update key with new value in JavaScript [SOLVED]

Use ipympl to solve JavaScript Error in IPython

Unlike the inline magic command, you can make use of a matplotlib package named ipympl which provides Jupyter integration and allows you to work with interactive plots within your matplotlib.

To have that, you need to install ipympl using either pip or conda depending on whether you are using a native python environment or an anaconda environment respectively.

To use pip, you can use the command below

pip install ipympl

However, if you use conda, you can use the command below

conda install -c conda-forge ipympl

Also, if you are using JupyterLab 2, you might need to follow the command below

conda install -c conda-forge nodejs
jupyter labextension install @jupyter-widgets/jupyterlab-manager jupyter-matplotlib

After installing the ipympl package, you can restart your JupyterLab and make use of the widget magic command to allow for interactive matplotlib within your code.

%matplotlib widget

Summary

To run interactive plots using matplotlib, you will need an extension — ipympl — to provide for such which relies on NodeJS to work, or you can render such a plot as a static plot using the inline magic command.

References

GitHub — matplotlib/ipympl: Matplotlib Jupyter Integration
https://matplotlib.org/ipympl/

Didn’t find what you were looking for? Perform a quick search across GoLinuxCloud

If you’re receiving the “JavaScript error: Ipython is not defined” message, it can be a bit confusing and frustrating to understand the cause of the error. However, don’t worry, this error is fixable, and there are a few solutions to help you resolve this issue. In this article, I’ll be guiding you through the reasons behind this error message and how to solve it.

What is Ipython?

Before getting to know about the error, we need to learn what IPython is.

IPython is an interactive command-line shell for Python. It provides an enhanced interactive environment for running and developing Python code. It offers features such as tab completion, command history, and debugging that are not present in the standard Python shell. IPython was originally developed to provide an enhanced terminal-based interface to Python. But it has since evolved to become a more general-purpose interactive computing environment.

When do we get the “Javascript error: IPython is not defined” error?

We encounter a “Javascript error: IPython is not defined” error while trying to run JavaScript code using the IPython library in Jupyter Notebook or another IPython environment. The message indicates that the IPython library is not available for use in your environment. This error occurs for various reasons. Most of the time, improper installation or setup of IPython causes this error.

Various ways of solving the “Javascript error: IPython is not defined” error?

IPython not installed properly, causing “Javascript error: IPython is not defined” error

One common cause of this error is that the IPython library is not correctly installed on your system. To check if IPython is installed, you can try importing it in a Jupyter Notebook cell using the following command:

import IPython

If IPython is not available, you will see an error message similar to “ModuleNotFoundError: No module named ‘IPython’”. To fix this issue, you can try installing IPython using pip:

!pip install IPython

If you are using Jupyter Notebook, you may also need to install the IPython kernel:

!pip install ipykernel

Once you install IPython, you should be able to import it without any issues, and the error message should disappear.

IPython incompatible with Jupyter notebook

Another common cause of the error is a problem with the version of IPython in use. In particular, if you are using an older version of IPython, it may not be compatible with the version of Jupyter or another IPython environment. To check the version of IPython you have installed, you can use the following command:

import IPython
print(IPython.__version__)

If you have an older version of IPython, try upgrading to the latest version by running the following command:

!pip install --upgrade IPython

When Running Jupyter Notebook in a Virtual Environment

Additionally, if you are running Jupyter Notebook in a virtual environment, you should ensure the activation status of the virtual environment before running your code. In some cases, the IPython library may not be available in the virtual environment, causing the “Javascript error: IPython is not defined” error. To check the activation status of the virtual environment, you can run the following command:

!which python

This command will show you the path to the Python executable that is currently in use by Jupyter Notebook. If the path does not match the location of the Python executable in your virtual environment, then you will need to activate your virtual environment before running Jupyter Notebook. To activate a virtual environment, you can use the following command:

source path/to/your/venv/bin/activate

Import IPython after the script

Finally, another cause can be the IPython library not being able to load properly. This happens if the IPython library import statement is being executed after the JavaScript code that uses the IPython library. We can fix this issue by making sure that the import statement for the IPython library is placed at the beginning of your script and that it is executed before any JavaScript code that uses the IPython library.

“Javascript error: IPython is not defined” while using autosave

The error message suggests that the JavaScript code that is being executed is trying to reference an object or variable named “Ipython,” which is not defined or not available in the current context.

This issue might be related to a library named autosave which is being used in the JavaScript code, and it might be trying to use the Ipython object in the code.

The library or module

is likely

supposed to provide the Ipython object, but it is missing or not correctly

loaded. One reason can be that the library or module is not present in the project or the import statement is missing.

It is suggested to check the implementation of the autosave library/module and make sure that it is adequately imported and configured.

“Javascript error: IPython is not defined” while using backtrader

It appears that the issue may not be related to the Backtrader library, as it is a python library for backtesting and trading strategy development. There might likely be confusion in the context or a typo in the code. To troubleshoot, you should recheck the code and make sure that a missing import statement, a typo in the variable name, a missing semicolon, or another syntax error does not cause the error.

Javascript error: Ipython is not defined while working in Kaggle

The error message “Ipython is not defined” suggests that there is a problem with the JavaScript code being executed. Specifically, the code is trying to access an object or variable named “Ipython,” which is not defined or not available in the current context. It seems that the error might be related to the Kaggle platform. As it could be that the code is trying to access some functionality provided by the platform, which is missing or not properly loaded.

To troubleshoot the problem, it is suggested to check the implementation of the Kaggle platform. Also, make sure that it is properly configured and that the necessary modules or packages are imported and loaded.

FAQs

How can a JavaScript code interact with the Ipython library?

You can use a JavaScript library that allows you to interact with an IPython kernel. The ‘jupyter-js-services’ and ‘jupyter-js-widgets’ libraries provide an API for interacting with an IPython kernel, so you can use these libraries to send code to the IPython kernel to be executed and receive the results back in JavaScript.

Is it recommended for JavaScript code to use the IPython kernel?

This is not recommended for heavy workloads as it might be costly for the browser and cause performance issues for your users.

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Python is one of the most popular programming languages to ever come out, mostly because it’s rather simple for beginners to understand but still powerful enough to write strong code often involving AI, ML and computer vision projects.

There are also hundreds of libraries available for the language that can integrate a number of different features. In this article, we’re taking a look at the “Javascript error: ipython is not defined” error that can come up when using Jupyter lab with Javascript and iPython. 

Also read: Is Python case sensitive when dealing with identifiers?


The solution for this is actually quite simple. As you might know already, Jupyter Labs supports interactive matplotlib graphs using the jupyter-matplotlib extension. You can install the extension using Conda or Pip by using the commands given below.

Using Pip

If you’re using Python’s in-built package manager Pip, here’s how you can install the jupyter-matplotlib extension for both Jupyter Labs and Jupyter Labs 2.

pip install ipympl

# If using JupyterLab 2
pip install nodejs
jupyter labextension install @jupyter-widgets/jupyterlab-manager
jupyter labextension install jupyter-matplotlib

Using Conda

Similar to Pip, Conda is also an open-source package manager that acts as an alternate source for many popular libraries. In case Pip doesn’t work for you, or you just prefer using Conda, you can use the following commands based on your situation to install jupyter-matplotlib.

conda install -c conda-forge ipympl

# If using JupyterLab 2
conda install nodejs
jupyter labextension install @jupyter-widgets/jupyterlab-manager
jupyter lab build

# Later, if updating a previous Lab install:
conda install ipympl
jupyter lab build

Once installed, you can use it by adding this line before plotting the graph.

%matplotlib widget

Alternatively, as a workaround you can also configure matplotlib to use inline instead of interactive. It’s not as powerful, but will sidestep the error for you. To use inline, simply add this line before plotting the graph.

%matplotlib inline

Also read: Fix: Python was not found; run without arguments to install 

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