Say I made complex numeric calculations with Scipy factories, using the Ipython notebook. Now, I want to call variables resulting from calculations with Scipy from code in Javascript (still within IPYNB).
Below is a simplistic illustration of what I am willing to accomplish:
# Get a vector of 4 normal random numbers using numpy - the variable 'rnd'
import numpy as np
mu, sig = 0.05, 0.2
rnd = np.random.normal(loc=mu, scale=sig, size=4)
Now, I want to use the variable rnd above in Javascript, for illustrative purpose:
%%javascript
element.append(rnd);
The lines above returns a message error: ReferenceError: rnd is not defined.
Then, how can one use a python variable in javascript code within the Ipython Notebook?
2 Answers 2
It may not be possible to do this with the %%Javascript cell magic. However you can use the IPython.display.Javascript(...) method to inject Python strings into the browser
output area. Here's a modification of your code fragment that seems to answer your question.
from IPython.display import Javascript
import numpy as np
mu, sig = 0.05, 0.2
rnd = np.random.normal(loc=mu, scale=sig, size=4)
## Now, I want to use the variable rnd above in Javascript, for illustrative purpose:
javascript = 'element.append("{}");'.format(str(rnd))
Javascript(javascript)
Paste this code into an input cell and each time you execute the cell a new and different array of random numbers will be displayed in the output cell.
(Code was tested with IPython version 2.2)
2 Comments
Arbitrary Python (including retrieving the value of variables) can be executed from the JavaScript side of things in IPython, although it is a bit messy. The following code works for me in IPython 3.1 and Python 2.7:
%%javascript
IPython.notebook.kernel.execute(
"<PYTHON CODE TO EXECUTE HERE>",
{
iopub: {
output: function(response) {
// Print the return value of the Python code to the console
console.log(response.content.data["text/plain"]);
}
}
},
{
silent: false,
store_history: false,
stop_on_error: true
}
)