大家好
最近在學習Python Data Visulization，利用一個叫做is_outlier的函數找出資料裡的outlier:
def is_outlier(points, threshold = 3.5):
if len(points.shape) == 1:
points = points[:,None]
median = np.median(points, axis = 0)
diff = np.sum((points = median)**2, axis = -1)
diff = np.sqrt(diff)
med_abs_deviation = np.median(diff)
modified_z_score = 0.6745*diff/med_abs/deviation
return modified_z_score > threshold
x = np.random.randmon(100)
x = no.r_[x, -49, 95, 100, -100]
filtered = x[~is_outlier(x)]
想請教大家，在函數內的points[:,None]是什麼意思?
還有為何filtered的值會是剔除outlier的numpy array呢?
是因為return modified_z_score > threshold這個判斷式會對整個array裡的值做判斷，然後True的值就放到filtered裡面嗎?