DataCamp

Customizing based on user input

Remember how in the plot from the previous exercise, the title did not update along with the slider? In this exercise, you'll fix this.

In Python, you can format strings by specifying placeholders with the % keyword. For example, if you have a string company = 'DataCamp', you can use print('%s' % company) to print DataCamp. Placeholders are useful when you are printing values that are not static, such as the value of the year slider. You can specify a placeholder for a number with %d. Here, when you're updating the plot title inside your callback function, you should make use of a placeholder so that the year displayed is in accordance with the value of the year slider.

In addition to updating the plot title, you'll also create the callback function and slider as you did in the previous exercise, so you get a chance to practice these concepts further.

All necessary modules have been imported for you, and as in the previous exercise, you may have to scroll to the right to view the entire figure.

Define the update_plot callback function with parameters attr, old and new.
Inside update_plot(), assign the value of the slider, slider.value, to yr and set source.data = new_data.
Inside update_plot(), specify plot.title.text to update the plot title and add it to the figure. You want the plot to update based on the value of the slider, which you have assigned above to yr. Make use of the placeholder syntax provided for you.
Make a slider object called slider using the Slider() function with a start year of 1970, end year of 2010, step of 1, value of 1970, and title of 'Year'.
Attach the callback to the 'value' property of slider. This can be done using on_change() and passing in 'value' and update_plot.

Take Hint (-30xp)

Exercise

Customizing based on user input

Instructions