ECDF function

empirical cumulative distribution function(ECDF) 經驗累積分布函數

def ecdf(data):
    """Compute ECDF for a one-dimensional array of measurements."""

    # Number of data points: n   
    n = len(data)

    # x-data for the ECDF: x
    x = np.sort(data)

    # y-data for the ECDF: y
    y = np.arange(1, n+1) / n

    #return x, y
    return x, y