Golang Instances.Set方法代碼示例

// Run applies a trained BinningFilter to a set of Instances,
// discretising any numeric attributes added.
//
// IMPORTANT: Run discretises in-place, so make sure to take
// a copy if the original instances are still needed
//
// IMPORTANT: This function panic()s if the filter has not been
// trained. Call Build() before running this function
//
// IMPORTANT: Call Build() after adding any additional attributes.
// Otherwise, the training structure will be out of date from
// the values expected and could cause a panic.
func (b *BinningFilter) Run(on *base.Instances) {
	if !b.trained {
		panic("Call Build() beforehand")
	}
	for attr := range b.Attributes {
		minVal := b.MinVals[attr]
		maxVal := b.MaxVals[attr]
		disc := 0
		// Casts to float32 to replicate a floating point precision error
		delta := float32(maxVal - minVal)
		delta /= float32(b.BinCount)
		for i := 0; i < on.Rows; i++ {
			val := on.Get(i, attr)
			if val <= minVal {
				disc = 0
			} else {
				disc = int(math.Floor(float64(float32(val-minVal) / delta)))
				if disc >= b.BinCount {
					disc = b.BinCount - 1
				}
			}
			on.Set(i, attr, float64(disc))
		}
		newAttribute := new(base.CategoricalAttribute)
		newAttribute.SetName(on.GetAttr(attr).GetName())
		for i := 0; i < b.BinCount; i++ {
			newAttribute.GetSysValFromString(fmt.Sprintf("%d", i))
		}
		on.ReplaceAttr(attr, newAttribute)
	}
}

// Run discretises the set of Instances `on'
//
// IMPORTANT: ChiMergeFilter discretises in place.
func (c *ChiMergeFilter) Run(on *base.Instances) {
	if !c._Trained {
		panic("Call Build() beforehand")
	}
	for attr := range c.Tables {
		table := c.Tables[attr]
		for i := 0; i < on.Rows; i++ {
			val := on.Get(i, attr)
			dis := 0
			for j, k := range table {
				if k.Value < val {
					dis = j
					continue
				}
				break
			}
			on.Set(i, attr, float64(dis))
		}
		newAttribute := new(base.CategoricalAttribute)
		newAttribute.SetName(on.GetAttr(attr).GetName())
		for _, k := range table {
			newAttribute.GetSysValFromString(fmt.Sprintf("%f", k.Value))
		}
		on.ReplaceAttr(attr, newAttribute)
	}
}