将一系列值映射到另一个值 [英] Mapping a range of values to another

问题描述

我正在寻找有关如何在 Python 中将一个范围值转换为另一个范围值的想法.我正在从事硬件项目，正在从可以返回一系列值的传感器读取数据，然后我使用这些数据来驱动需要不同范围值的执行器.

I am looking for ideas on how to translate one range values to another in Python. I am working on hardware project and am reading data from a sensor that can return a range of values, I am then using that data to drive an actuator that requires a different range of values.

例如，假设传感器返回 1 到 512 范围内的值，执行器由 5 到 10 范围内的值驱动.我想要一个函数，我可以传递一个值和两个范围并得到返回映射到第二个范围的值.如果这样的函数被命名为 translate，它可以像这样使用:

For example lets say that the sensor returns values in the range 1 to 512, and the actuator is driven by values in the range 5 to 10. I would like a function that I can pass a value and the two ranges and get back the value mapped to the second range. If such a function was named translate it could be used like this:

sensor_value = 256
actuator_value = translate(sensor_value, 1, 512, 5, 10)

在此示例中，我希望输出 actuator_value 为 7.5，因为 sensor_value 处于可能输入范围的中间.

In this example I would expect the output actuator_value to be 7.5 since the sensor_value is in the middle of the possible input range.

推荐答案

一种解决方案是:

def translate(value, leftMin, leftMax, rightMin, rightMax):
    # Figure out how 'wide' each range is
    leftSpan = leftMax - leftMin
    rightSpan = rightMax - rightMin

    # Convert the left range into a 0-1 range (float)
    valueScaled = float(value - leftMin) / float(leftSpan)

    # Convert the 0-1 range into a value in the right range.
    return rightMin + (valueScaled * rightSpan)

您可以使用代数来提高效率，但会牺牲可读性.

You could possibly use algebra to make it more efficient, at the expense of readability.

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