Using Ipython ipywidget to create a variable?

Question

This seems really simple but I have not been able to find a single example or to solve this myself. How do I use an ipywidget widget to create or return a python variable/object, such as a list or string, that can be used in a following cell?

Answer 1

There is a good introduction to ipywidgets at http://blog.dominodatalab.com/interactive-dashboards-in-jupyter/ which answers this question.

You need two widgets, one for input, and another to bind the value of that input. Here's an example for text input:

from ipywidgets import widgets    # Create text widget for output output_text = widgets.Text()  # Create text widget for input input_text = widgets.Text()  # Define function to bind value of the input to the output variable  def bind_input_to_output(sender):     output_text.value = input_text.value  # Tell the text input widget to call bind_input_to_output() on submit input_text.on_submit(bind_input_to_output)  # Display input text box widget for input input_text  # Display output text box widget (will populate when value submitted in input) output_text  # Display text value of string in output_text variable output_text.value  # Define new string variable with value of output_text, do something to it uppercase_string = output_text.value.upper() print uppercase_string 

You can then use the uppercase_string, or output_text.value string, for example, throughout your notebook.

A similar pattern can be followed for using other input values, e.g. the interact() slider:

from ipywidgets import widgets, interact  # Create text widget for output output_slider_variable = widgets.Text()  # Define function to bind value of the input to the output variable  def f(x):     output_slider_variable.value = str(x)  # Create input slider with default value = 10     interact(f, x=10)  # Display output variable in text box output_slider_variable  # Create and output new int variable with value of slider new_variable = int(output_slider_variable.value) print new_variable  # Do something with new variable, e.g. cube new_variable_cubed = pow(new_variable, 3) print new_variable_cubed