percentChange# swordfish.function.percentChange()# For each element Xi in X, return (Xi / Xi-n) - 1, representing the percentage changes between elements. 参数: X (Constant) -- A vector or matrix. n (Constant, optional) -- An integer specifying the step to shift when comparing elements in X. The default value is 1, meaning to compare the current element with the adjacent element at left. 返回: A vector or matrix with the same shape as X. 返回类型: Constant