Thanks to Thomas, here is the solution I was looking for:

    from IPython.core.interactiveshell import InteractiveShell
    InteractiveShell.ast_node_interactivity = &quot;all&quot;

https://www.dataquest.io/blog/jupyter-notebook-tips-tricks-shortcuts/

1) Place this code in a Jupyter cell:


    from IPython.core.interactiveshell import InteractiveShell

    InteractiveShell.ast_node_interactivity = &quot;all&quot;

2) In Windows, the steps below makes the change permanent. Should work for other operating systems. You might have to change the path.

    C:\Users\your_profile\\.ipython\profile_default

Make a ipython_config.py file in the profile_defaults with the following code:

    c = get_config()

    c.InteractiveShell.ast_node_interactivity = &quot;all&quot;

# **Per Notebook Basis**
 As others have answered, putting the following code in a Jupyter Lab or Jupyter Notebook cell will work:
```
from IPython.core.interactiveshell import InteractiveShell

InteractiveShell.ast_node_interactivity = &quot;all&quot;
```

# Permanent Change
However, if you would like to make this permanent and use Jupyter Lab, you will need to create an IPython notebook config file. Run the following command to do so (**DO NOT** run if you use Jupyter Notebook - more details below):
```
ipython profile create
```
If you are using Jupyter Notebook, this file should have already been created and there will be no need to run it again. In fact, running this command **may overwrite** your current preferences. 


Once you have this file created, for Jupyter Lab and Notebook users alike, add the following code to the file ``C:\Users\USERNAME\.ipython\profile_default\ipython_config.py``:
```
c.InteractiveShell.ast_node_interactivity = &quot;all&quot;
```
I found there is no need for  ``c = get_config()`` in the newer versions of Jupyter, but if this doesn&#39;t work for you, add the ``c = get_config()`` to the beginning of the file.


For more flag options other than ``&quot;all&quot;``, visit [this](https://ipython.readthedocs.io/en/stable/config/options/terminal.html#configtrait-InteractiveShell.ast_node_interactivity) link:
https://ipython.readthedocs.io/en/stable/config/options/terminal.html#configtrait-InteractiveShell.ast_node_interactivity

I have ruby installed on my ubuntu 16.04.

    $which ruby  
    
    /usr/bin/ruby

    $ruby -v 
    
    ruby 2.3.0p0 (2015-12-25) [x86_64-linux-gnu]

    $gem install bundler 
    
    ERROR:  While executing gem ... (Gem::FilePermissionError)
        You don&#39;t have write permissions for the /var/lib/gems/2.3.0 directory.

You don&#39;t have write permissions for the /var/lib/gems/2.3.0 directory

When I try to symlink a binary in my /usr/bin folder, I get an Operation not permitted error:

     sudo ln -s /usr/bin/python2.7 /usr/bin/python2
    ln: /usr/bin/python2: Operation not permitted

Even as sudo, I get this error.

Cannot create a symlink inside of /usr/bin even as sudo

I want Jupyter to print all the interactive output without resorting to print, not only the last result. How to do it?

Example : 

    a=3
    a
    a+1

I would like to display

&gt; 3  
&gt; 4

How to display full output in Jupyter, not only last result?

I want Jupyter to print all the interactive output without resorting to print, not only the last result. How to do it?
Example :
<pre><code class="hljs language-css">a=3
a
a+1
</code></pre>
I would like to display
> 3 
> 4

Surprisingly, there&#39;s no explicit documentation for `__weakref__`. Weak references are explained [here][1]. `__weakref__` is also shortly mentioned in the documentation of `__slots__`. But I could not find anything about `__weakref__` itself.

What exactly is `__weakref__`?
- Is it just a member acting as a flag: If present, the object may be weakly-referenced?
- Or is it a function/variable that can be overridden/assigned to get a desired behavior? How?


  [1]: https://docs.python.org/2/library/weakref.html

What exactly is __weakref__ in Python?

I want to use `multiprocessing` on a large dataset to find the distance between two gps points. I constructed a test set, but I have been unable to get `multiprocessing` to work on this set.

    import pandas as pd
    from geopy.distance import vincenty
    from itertools import combinations
    import multiprocessing as mp
    
    df = pd.DataFrame({&#39;ser_no&#39;: [1, 2, 3, 4, 5, 6, 7, 8, 9, 0],
                    &#39;co_nm&#39;: [&#39;aa&#39;, &#39;aa&#39;, &#39;aa&#39;, &#39;bb&#39;, &#39;bb&#39;, &#39;bb&#39;, &#39;bb&#39;, &#39;cc&#39;, &#39;cc&#39;, &#39;cc&#39;],
                    &#39;lat&#39;: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10],
                    &#39;lon&#39;: [21, 22, 23, 24, 25, 26, 27, 28, 29, 30]})
    
    
    
    def calc_dist(x):
        return pd.DataFrame(
                   [ [grp,
                      df.loc[c[0]].ser_no,
                      df.loc[c[1]].ser_no,
                      vincenty(df.loc[c[0], x], 
                               df.loc[c[1], x])
                     ]
                     for grp,lst in df.groupby(&#39;co_nm&#39;).groups.items()
                     for c in combinations(lst, 2)
                   ],
                   columns=[&#39;co_nm&#39;,&#39;machineA&#39;,&#39;machineB&#39;,&#39;distance&#39;])
                   
    if __name__ == &#39;__main__&#39;:
        pool = mp.Pool(processes = (mp.cpu_count() - 1))
        pool.map(calc_dist, [&#39;lat&#39;,&#39;lon&#39;])
        pool.close()
        pool.join()

I am using Python 2.7.11 and Ipython 4.1.2 with Anaconda 2.5.0 64-bit on Windows7 Professional when this error occurs.

&gt;runfile(&#39;C:/.../Desktop/multiprocessing test.py&#39;, wdir=&#39;C:/.../Desktop&#39;)
Traceback (most recent call last):

 &gt;File &quot;&lt;ipython-input-18-a3443409b86b&gt;&quot;, line 1, in &lt;module&gt;
    runfile(&#39;C:/.../Desktop/multiprocessing test.py&#39;, wdir=&#39;C:/.../Desktop&#39;)

 &gt;File &quot;C:\...\Local\Continuum\Anaconda2\lib\site-packages\spyderlib\widgets\externalshell\sitecustomize.py&quot;, line 699, in runfile
    execfile(filename, namespace)

 &gt;File &quot;C:\...\Local\Continuum\Anaconda2\lib\site-packages\spyderlib\widgets\externalshell\sitecustomize.py&quot;, line 74, in execfile
    exec(compile(scripttext, filename, &#39;exec&#39;), glob, loc)

 &gt;File &quot;C:/..../multiprocessing test.py&quot;, line 33, in &lt;module&gt;
    pool.map(calc_dist, [&#39;lat&#39;,&#39;lon&#39;])

 &gt;File &quot;C:\...\AppData\Local\Continuum\Anaconda2\lib\multiprocessing\pool.py&quot;, line 251, in map
    return self.map_async(func, iterable, chunksize).get()

 &gt;File &quot;C:\...\Local\Continuum\Anaconda2\lib\multiprocessing\pool.py&quot;, line 567, in get
    raise self._value

&gt;TypeError: Failed to create Point instance from 1.

    def get(self, timeout=None):
        self.wait(timeout)
        if not self._ready:
            raise TimeoutError
        if self._success:
            return self._value
        else:
            raise self._value



Python: using multiprocessing on a pandas dataframe

In python 3.x, it is common to use return type annotation of a function, such as:

    def foo() -&gt; str:
        return &quot;bar&quot;

What is the correct annotation for the &quot;void&quot; type?

I&#39;m considering 3 options:

 1. ``def foo() -&gt; None:``
      - not logical IMO, because ``None`` is not a type,
 2. ``def foo() -&gt; type(None):``
      - using the best syntax I know for obtaining ``NoneType``,
 3. ``def foo():``
      - omit explicit return type information.

Option 2. seems the most logical to me, but I&#39;ve already seen some instances of 1.

Python void return type annotation

I am using [`pytest`][1], and the test execution is supposed to run until it encounters an exception. If the test never encounters an exception it should continue running for the rest of time or until I send it a SIGINT/SIGTERM.

Is there a programmatic way to tell `pytest` to stop running on the first failure as opposed to having to do this at the command line?


  [1]: https://docs.pytest.org/en/latest/

long running py.test stop at first failure

I am writing some data into an Excel file, but I dont know how to adjust the code in order to be able to control which sheet I am writing into:

    wb = load_workbook(filename)
    active_ws = wb.active

Instead of `wb.active`, how can I say something like `Sheets(&#39;Data&#39;)` (this is how the VBA syntax would look like...)?

openpyxl get sheet by name

I have jupyter/anaconda/python3.5.


1. How can I know which conda environment is my jupyter notebook running on?    

2. How can I launch jupyter from a new conda environment?

In which conda environment is Jupyter executing?

In my notebook, I have a cell returning temp calculation results. It&#39;s a bit long, so after it is run, I want to hide it and when needed, to show it.

To do it manually, I can double click the left side of the output, to hide it

[![enter image description here][1]][1]

After double click
[![enter image description here][2]][2]

But is there any way I can do this by code? For example,

the last line of the cell, use a command like `%%hide output`, and the output would be hidden after finished running.

Additionally, can I get this feature in output HTML?

  [1]: http://i.stack.imgur.com/H6M4H.png
  [2]: http://i.stack.imgur.com/O0u57.png

Jupyter Notebook: command for hide the output of a cell?

I&#39;m trying to set a good environnement for doing some scientific stuff with python. To do so, I installed Jupyter &amp; miniconda.

Then I want to be able to have different environnement and use them with Jupyter notebooks. So I created two custom envs with conda : py27 and py35.

    &gt; conda env list
    # conda environments:
    #
    py27                     /Users/***/miniconda3/envs/py27
    py35                     /Users/***/miniconda3/envs/py35
    root                  *  /Users/***/miniconda3

Then on my notebook I have two kernels `python 2` and `python 3`.
Inside a notebook, I get the following with the python3 kernel :

    &gt; import sys
    &gt; print(sys.executable)
    /Users/***/miniconda3/envs/py35/bin/python


And this with the python2 kernel :

    &gt; import sys
    &gt; print(sys.executable)
    /usr/local/opt/python/bin/python2.7


 - How can I set the `sys.executable` to miniconda env for python2 ?
 - How can I bind a conda env with a notebook kernel ?
 - Is doing `source activate py35` has a link with `jupyter notebook` ?

I think I really missed something.

Thank you everyone.

--- edit

I have multiple jupyter bin :

    &gt; where jupyter
    /usr/local/bin/jupyter
    /usr/local/bin/jupyter
    /Users/ThomasDehaeze/miniconda3/bin/jupyter

I have only one kernel here `/usr/local/share/jupyter/kernels/python2`.
But inside Jupyter, I have two kernels, `python2` and `python3`. Where can I find the other one ?

---

I modified `kernel.json` from `/usr/local/share/jupyter/kernels/python2` :

    {
     &quot;display_name&quot;: &quot;Python 2&quot;,
     &quot;language&quot;: &quot;python&quot;,
     &quot;argv&quot;: [
      &quot;/Users/***/miniconda3/envs/py27/bin/python2.7&quot;,
      &quot;-m&quot;,
      &quot;ipykernel&quot;,
      &quot;-f&quot;,
      &quot;{connection_file}&quot;
     ]
    }

And then :

    import sys
    print(sys.executable)
    /usr/local/opt/python/bin/python2.7

So nothing has changed

Link Conda environment with Jupyter Notebook

How do you convert an IPython notebook file (json with `.ipynb` extension) into a regular `.py` module?

Convert JSON IPython notebook (.ipynb) to .py file

When I run `!pip install geocoder` in Jupyter Notebook I get the same output as running `pip install geocoder` in the terminal but the geocoder package is not available when I try to import it.

I&#39;m using Ubuntu 14.04, Anaconda 4.0.0 and pip 8.1.2

**Installing geocoder:**

    !pip install geocoder

    The directory &#39;/home/ubuntu/.cache/pip/http&#39; or its parent directory is not owned by the current user and the cache has been disabled. Please check the permissions and owner of that directory. If executing pip with sudo, you may want sudo&#39;s -H flag.
    The directory &#39;/home/ubuntu/.cache/pip&#39; or its parent directory is not owned by the current user and caching wheels has been disabled. check the permissions and owner of that directory. If executing pip with sudo, you may want sudo&#39;s -H flag.
    Collecting geocoder
      Downloading geocoder-1.15.1-py2.py3-none-any.whl (195kB)
        100% |████████████████████████████████| 204kB 3.2MB/s 
    Requirement already satisfied (use --upgrade to upgrade): requests in /usr/local/lib/python2.7/dist-packages (from geocoder)
    Requirement already satisfied (use --upgrade to upgrade): ratelim in /usr/local/lib/python2.7/dist-packages (from geocoder)
    Requirement already satisfied (use --upgrade to upgrade): six in /usr/local/lib/python2.7/dist-packages (from geocoder)
    Requirement already satisfied (use --upgrade to upgrade): click in /usr/local/lib/python2.7/dist-packages (from geocoder)
    Requirement already satisfied (use --upgrade to upgrade): decorator in /usr/local/lib/python2.7/dist-packages/decorator-4.0.10-py2.7.egg (from ratelim-&gt;geocoder)
    Installing collected packages: geocoder
    Successfully installed geocoder-1.15.1

**Then try to import it:**

    import geocoder

    ---------------------------------------------------------------------------
    ImportError                               Traceback (most recent call last)
    &lt;ipython-input-4-603a981d39f2&gt; in &lt;module&gt;()
    ----&gt; 1 import geocoder
    
    ImportError: No module named geocoder

I also tried shutting down the notebook and restarting it without any luck.

**Edit:** I found that using the terminal installs the geocoder package in `/home/ubuntu/.local/lib/python2.7/site-packages` and using a notebook installs it in `/usr/local/lib/python2.7/dist-packages` which is not in the path. `sys.path.append(&#39;/usr/local/lib/python2.7/dist-packages&#39;)` solves the problem for the current session.

So how can I permanently modify the path or tell pip where to install geocoder?

Installing a pip package from within a Jupyter Notebook not working

I&#39;ve gotten myself into some kind of horrible virtualenv mess.  Help?!

I manage environments with `conda`.  Until recently, I only had a python2 jupyter notebook kernel, but I decided to drag myself kicking and screaming into the 21st century and installed a python3 kernel; I forget how I did it.  

My main (anaconda) python defaults to 2.7.  

So here I am, merrily trying to use beautiful soup from inside my shiny new python3 kernel, and I don&#39;t seem to be able to do anything to get at whatever environment it&#39;s finding packages in.  Viz (all from notebook): 

    from bs4 import BeautifulSoup 
    
    -&gt; ImportError: No module named &#39;bs4&#39;

Ok, fine, I&#39;ll install it using shell magic.  Right?  Right? 

    ! pip install bs4
    
    --&gt; Collecting bs4
      Downloading bs4-0.0.1.tar.gz
    Requirement already satisfied (use --upgrade to upgrade): beautifulsoup4 in /Users/[MY-USER]/anaconda/lib/python2.7/site-packages (from bs4)
    [...]
    Successfully built bs4
    Installing collected packages: bs4
    Successfully installed bs4-0.0.1

    from bs4 import BeautifulSoup 
    
    -&gt; ImportError: No module named &#39;bs4&#39;

Oh no.  Does it think I&#39;m in a 2.7 env even though I&#39;m running a python3 kernel?  That won&#39;t do.  

    ! conda info --envs
    --&gt; # conda environments:
    #
    flaskenv                 /Users/[MY-USER]/anaconda/envs/flaskenv
    mesa                     /Users/[MY-USER]/anaconda/envs/mesa
    py35                     /Users/[MY-USER]/anaconda/envs/py35
    root                  *  /Users/[MY-USER]/anaconda

Ok, I can fix that. One of those is a 3.5 env.

    ! source activate py35
    --&gt; prepending /Users/[MY-USER]/anaconda/envs/py35/bin to PATH

    ! conda install beautifulsoup4
    --&gt; Fetching package metadata .......
    Solving package specifications: ..........
    
    # All requested packages already installed.
    # packages in environment at /Users/[MY-USER]/anaconda:
    #
    beautifulsoup4            4.4.1                    py27_0  

concerning... 

    ! pip install bs4
    --&gt; Requirement already satisfied (use --upgrade to upgrade): bs4 in /Users/[MY-USER]/anaconda/lib/python2.7/site-packages

more concerning... 

    from bs4 import BeautifulSoup 
    
    -&gt; ImportError: No module named &#39;bs4&#39;

ARRGH!!!  *headdesk*  Am I going to have to kill the kernel in order to fix this (and re-run a bit of work)?  Is killing the kernel even going to work?  How do I get my jupyter kernel to know what environment it&#39;s supposed to be running under?

thanks!

jupyter notebook running kernel in different env

The official way to visualize a TensorFlow graph is with TensorBoard, but sometimes I just want a quick look at the graph when I&#39;m working in Jupyter.

Is there a quick solution, ideally based on TensorFlow tools, or standard SciPy packages (like matplotlib), but if necessary based on 3rd party libraries?

Content Type	Original Author	Original Content on Stackoverflow
Question	mbh86	View Question on Stackoverflow
Solution 1 - Python	mbh86	View Answer on Stackoverflow
Solution 2 - Python	William	View Answer on Stackoverflow
Solution 3 - Python	Ani Aggarwal	View Answer on Stackoverflow

How to display full output in Jupyter, not only last result?

Python Problem Overview

Python Solutions

Solution 1 - Python

Solution 2 - Python

Solution 3 - Python

Per Notebook Basis

Permanent Change

Cannot create a symlink inside of /usr/bin even as sudo

You don't have write permissions for the /var/lib/gems/2.3.0 directory

Attributions