Question

ValueError：索引必须是单调递增或递减 [Jupyter笔记本图片] [1]

我正在练习 python书中的上述代码片段，以供Wes McKinney进行数据分析

我这样创建一个DataFrame

frame=DataFrame(np.arange(9).reshape((3,3)), index=['a','c','d'], columns=['Ohio','Texas','California'])

当我尝试像这样重新索引它时：

states=['Texas','Utah','California']
frame.reindex(index=['a','b','c','d'],method='ffill', columns=states)

为什么会引发ValueError？

Answer 1

你可以使用

extension SKAction {
    static func diagonalRotate(duration: TimeInterval) -> SKAction {
        return SKAction.customAction(withDuration: duration) {
            node, elapsedTime in
 
            if let node = node as? SKTransformNode {
                // should be Float.pi to do half a revolution,
                // but the problem starts to occur nearby 0.667 * CGFloat.pi
                let angle = 0.667 * Float.pi * (Float(elapsedTime) / Float(duration))
                let c = cos(angle)
                let s = sin(angle)
                let xRot = matrix_float3x3([[1, 0, 0],
                                          [0, c, -s],
                                          [0, s, c]])
                let yRot = matrix_float3x3([[c, 0, s],
                                          [0, 1, 0],
                                          [-s, 0, c]])
                // matrix for diagonal rotation where South East becomes North West
                dRot = (xRot + yRot) * 0.5
                print("angle: \(angle)\tcos: \(c)\tsin: \(s)")
                print("dRot matrix: \(dRot)")
                node.setRotationMatrix(dRot)
                print("node matrix: \(node.rotationMatrix())")
            }
        }
    }
}

使用method ='ffill'时重新索引错误

1 个答案: