Display multiple channels of data

Python GUI programming Day 3

With what you have learned from Day2, you will learn how to create a GUI that displays multiple channels of data in this session. The widget we need is plotting widget, which is used to display the data.

Python_GUI_day3_simple.py is the template that displays data generated by the program in three channels.

Python_GUI_day3_file.py is the template that displays data from a file.

Display data of three channels generated by program

The code is the same as Day2. We just need to add more plot widgets to the GUI. We could simply duplicate the code for one plot widget and change the name of the widget. However, this can make the codes look messy. A better way is to use a loop to create the widgets.

In order to use a loop, we need to use zip function. The zip function is used to combine two lists. For example, if we have two lists, list1 = [1,2,3] and list2 = [4,5,6], we can use zip function to combine them into a list of tuples: [(1,4),(2,5),(3,6)]. By doing so, you can index the first element of each tuple by [0] and the second element by [1]. That's it. You can read more about how to use zip in the tutoria from Real Python.

One more thing before you proceed is that you need to generate data for each channel. The code is shown in Python_GUI_day3_simple.py.

Display data of three channels from file

Now try to display the data in three channles from the file you processed in Day 2. There are three channels in the file. You can use the following code to read the data from the file:

filename = 'Data/charis4.dat'
with open(filename, 'rb') as datafile:
    data = np.fromfile(datafile, np.dtype('int16'))
ABP  = (data[0::3]+2644)/91.5061
ECG  = (data[1::3]+392)/6081.8245    
ICP  = (data[2::3]+5)/84.0552

The full codes are shown in Python_GUI_day3_file.py. Try to code by yourself before you check the codes.