Develop Reference

How can I configure a line chart using pivot_ui?

I would like to create a dynamic line chart in Voila. How can I manipulate the below code to show a standard line graph where the x axis equals column "a" and the y axis equals column "b"? Potentially the user can then dynamically update the output to make the y axis equal to column "c" by drag and drop etc.
from pivottablejs import pivot_ui
import pandas as pd
import IPython
df = pd.DataFrame(("a": [1,2,3], "b": [30,45,60],"c": [100,222,3444]))
display.display(df)
pivot_ui(df,outfile_path='pivottablejs.html',
rendererName="Line Chart",
cols= ["b","c"]
rows= ["a"],
aggregatorName="Sum"
)
display.display(IPython.display.HTML('pivottablejs.html"))
Thank you.

This should be a comment but I cannot post code with comments easily.
Please always test your code, preferably in a new notebook so it is fresh kerenl, before you post it.
Your dataframe assignment won't work. Should it be something like below?
That display code won't work in Jupyter notebook classic or JupyterLab presently.
Try something like this for assignment and display:
import pandas as pd
df = pd.DataFrame({"a": [1,2,3], "b": [30,45,60],"c": [100,222,3444]})
display(df)
That works in the classic notebook, JupyterLab, and Voila to make & display the dataframe.
Related to this is that is advisable to develop for Voila in JupyterLab. JupyterLab's rendering machinery is more modern and so closer to what Voila uses.
You can easily test renderings in launches from the Voila binder example page. Go there and click 'launch binder for the appropriate rendering. From JupyterLab you can select the Voila icon from the toolbar just above an open notebook and get the Voila rendering on the side.

Can't display Latex expressions in pandas using Google collab

Hello I have a problem that I cant display a simple pandas table whitch has Latex expressions in it.
I have a simple python script:
x = 1;
x1 = 2;
my_dict = {'Case1':{'Formula1':'$$x^{-1}$$', 'Formula2':'$$x^2$$', 'Formula3':x},
'Case2':{'Formula1':'$$x^{-2}$$', 'Formula2':'$$x^4$$', 'Formula3':x1}}
df = pd.DataFrame(my_dict)
display(df.transpose())
When I am using Jupyter Notebook it works fine like this:
Example in Jupyter Notebook
but when I opened the same code in Google collab it is showing like this:
Formula1 Formula2 Formula3
Case1 $$x^{-1}$$ $$x^2$$ 1
Case2 $$x^{-2}$$ $$x^4$$ 2
Is there something I can do to make Google collab display it like Jupyter notebook ?

You could use something like:
from IPython.display import Math
Math('$$x^{-1}$$')
This wouldn't work for the cells inside the table, but I don't think there's any way to override pandas' behavior, so you might have to write your own code to print the table out with the formulas intact.
You could also do
import pandas as pd
from IPython.display import Markdown
v = pd.DataFrame({'Case1':{'Formula1':'$$x^{-1}$$', 'Formula2':'$$x^2$$', 'Formula3':1},
'Case2':{'Formula1':'$$x^{-2}$$', 'Formula2':'$$x^4$$', 'Formula3':2}})
display(Markdown(str(v)))
but the table formatting is broken.

Get only the code out of Jupyter Notebook

Is there a solution to pull out all the code of the notebook?
For example, if I wanted to generate a source file of my notebook "source.py" that contained all the code in the code cells of the notebook, is that possible?
Thanks!

nbconvert
You can use the command line tool nbconvert to convert the ipynb file to various other formats.
The easiest way to convert it to a .py file is:
jupyter nbconvert --no-prompt --to script notebook_name.ipynb
It outputs only the code and comments without the markdown, input and output prompts. There is also --stdout option.
nbconvert documentation
jq
But you can also just parse the JSON of the notebook using jq:
jq -j '
.cells
| map( select(.cell_type == "code") | .source + ["\n\n"] )
| .[][]
' \
notebook.ipynb > source.py
jq homepage
Jupyter Notebook format

You can do File -> Download as -> Python (.py) — this should export all code cells as single .py file

In case you are using jupyter lab then the option is:
File > Export Notebook As > Executable Script

Since the notebook format is JSON it's relatively easy to extract just the text content of only the code cells. The task is made even easier when you use the Python API for working with notebook files.
The following will get you the code on standard output. You can handle it in other ways similarly easily. Bear in mind code source may not have a terminating newline.
from nbformat import read, NO_CONVERT
with open("Some Notebook.ipynb") as fp:
notebook = read(fp, NO_CONVERT)
cells = notebook['cells']
code_cells = [c for c in cells if c['cell_type'] == 'code']
for cell in code_cells:
print(cell['source'])
Notebook nodes are a little more flexible than dictionaries, though, and allow attribute (.name) access to fields as well as subscripting (['name']). As a typing-challenged person I find it preferable to write
cells = notebook.cells
code_cells = [c for c in cells if c.cell_type == 'code']
for cell in code_cells:
print(cell.source)
In answering this question I became aware that the nbformat library has been unbundled, and can therefore be installed with pip without the rest of Jupyter.

There is an "ugly" solution. Select all the cells of your notebook. Merge them, then just copy and paste all the code.

Dataframe head not shown in PyCharm

I have the following code in PyCharm
import pandas as pd
import numpy as np
import matplotlib as plt
df = pd.read_csv("c:/temp/datafile.txt", sep='\t')
df.head(10)
I get the following output:
Process finished with exit code 0
I am supposed to get the first ten rows of my datafile, but these do not appear in PyCharm.
I checked the Project interpreter and all settings seem to be alright there. The right packages are installed (numpy, pandas, matplotlib) under the right Python version.
What am I doing wrong? Thanks.

PyCharm is not Python Shell which automatically prints all results.
In PyCharm you have to use print() to display anything.
print(df.head(10))
The same is when you run script in other IDE or editor or directly python script.py

For printing all data
print(df)
By Default it will print top 5 records for head.
print(df.head())
If you need 10 rows then you can write this way
print(df.head(10))

I did File-Invalidate Caches/Restart Option Invalidate and after that I was able to get the head:

How do I save a Beaker notebook as straight python/r/...?

I just discovered Beaker Notebook. I love the concept, and am desperately keen to use it for work. To do so, I need to be sure I can share my code in other formats.
Question
Say I write pure Python in a Beaker notebook:
Can I save it as a .py file as I can in iPython Notebook/Jupyter?
Could I do the same if I wrote a pure R Beaker notebook?
If I wrote a mixed (polyglot) notebook with Python and R, can I save this to e.g. Python, with R code present but commented out?
Lets say none of the above are possible. Looking at the Beaker Notebook file as a text file, it seems to be saved in JSON. I can even find the cells that correspond to e.g. Python, R. It doesn't look like it would be too challenging to write a python script that does 1-3 above. Am I missing something?
Thanks!
PS - there's no Beaker notebook tag!? bad sign...

It's really not that hard to replicate the basics of the export:
#' Save a beaker notebook cell type to a file
#'
#' #param notebook path to the notebook file
#' #param output path to the output file (NOTE: this file will be overwritten)
#' #param cell_type which cells to export
save_bkr <- function(notebook="notebook.bkr",
output="saved.py",
cell_type="IPython") {
nb <- jsonlite::fromJSON(notebook)
tmp <- subset(nb$cells, evaluator == cell_type)$input
if (length(tmp) != 0) {
unlink(output)
purrr::walk(tidyr::unnest(tmp, body), cat, file=output, append=TRUE, sep="\n")
} else {
message("No cells found matching cell type")
}
}
I have no idea what Jupyter does with the "magic" stuff (gosh how can notebook folks take that seriously with a name like "magic").
This can be enhanced greatly, but it gets you the basics of what you asked.