Porting the Observer Pattern to Python

Porting a simplified version of the Weather Observer program to Python proved to be pretty straight forward, especially since most of the classes and methods were already provided to us ported over. The one issue I initially encountered came when I tried to implement humidity into the display. My first thought was to simply copy the following method:

    def setTemperature(self, temperature):
        self.temperature = temperature

and create another version for Humidity:

    def setHumidity(self, humidity):
        self.humidity = humidity

I then would call each method in the driver to set a value using:


The problem with this was that as soon as the program got through the setTemperature method it would then notify the observers without running through the setHumidity method and the output would initially be 78.0 and None, rather than 78.0 and 30.0.

When I finally tracked down what was happening it occurred to me to make a single setMeasurements method as below:

    def setMeasurements(self, temperature, humidity):
        self.temperature = temperature
        self.humidity = humidity
weatherData.setMeasurements(78.0, 30.0)

Once I implemented those changes the appropriate output was produced:

Current Conditions: 78.0F degrees and 30.0% humidity

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