映射值的范围，以另一 [英] Mapping a range of values to another

问题描述

我要寻找关于如何在Python转换一个量程值到另一个想法。我工作的硬件项目和正在读来自传感器的数据，可以返回一个值的范围，我然后使用该数据来驱动需要不同范围的值的驱动器。

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.

举例来说可以说，该传感器的范围为1〜512返回值，执行机构是由价值驱动的取值范围为5至10。我想，我可以传递一个值和两个范围，并得到一个功能背映射到所述第二范围的值。如果这样的功能被命名为翻译它可以像这样使用：

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)

在这个例子中，我期望的输出 actuator_value 是 7.5 ，因为如Sensor_value 是在可能的输入范围的中间

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

一个解决办法是：

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)

你可能用代数，使之更有效率，在可读性为代价的。

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

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