Keep trying getting the TypeError: '<' not supported between instances of 'int&#03-CodePudding

I've been trying all day to have the max/min values inside of a csv file. I try to put them in an array and find the max/min value inside said array but I either get TypeError: '<' not supported between instances of 'int' and 'list' or 'float object not iterable'. If I could get some pointers on where to start correcting this code, I would appreciate it.

def get_readings_from_file(filename: str, skip_first_line: bool) -> list[WeatherReading]:

    with open(filename, "r") as file:
        
        all_readings: list[WeatherReading] = []
        maxHum, maxTemp, minPress = [], [], []
        first_line = True

        for line in file:

            if skip_first_line and first_line:
                first_line = False
                continue

            def max_temperature(a):
                return max(a)

            def max_humidity(b):
                return max(b)

            def min_pressure(c):
                return min(c)

            split = line.split(",")

            temperature = float(split[0])
            maxTemp.append(temperature)
            max_temperature(maxTemp)

            pressure = float(split[1])
            minPress.append(pressure)
            min_pressure(minPress)

            humidity = float(split[2])
            maxHum.append(humidity)
            max_humidity(maxHum)

            if valid_reading(maxTemp, minPress, maxHum):
                reading = WeatherReading(maxTemp, minPress, maxHum)
                all_readings.append(reading)

        return all_readings

CodePudding user response：

You have this:

if valid_reading(maxTemp, minPress, maxHum):

Passing maxTemp etc. to valid_reading. valid_reading expects floating point numbers, but the arguments you're passing are in fact lists of these values, and thus you get the error if you run get_readings_from_file.

CodePudding user response：

It is because you forget to change your lists to their min/max:

maxTemp = max_temperature(maxTemp)  # instead of simply 'max_temperature(maxTemp)'
minPress = min_pressure(minPress)
maxHum = max_humidity(maxHum)

If I can give an advice: you should avoid changing the type of your variables and you can use mypy module to help you catching this kind of error.