Numpy 基礎運算2
阿新 • • 發佈：2019-02-11
spa 兩個 average 最小值 merge copyright 中位數 diff nco
# -*- encoding:utf-8 -*- # Copyright (c) 2015 Shiye Inc. # All rights reserved. # # Author: ldq <[email protected]> # Date: 2019/2/11 14:57 import numpy as np a = np.arange(2, 14).reshape(3, 4) ‘‘‘ reshape矩陣變維 [[ 2 3 4 5] [ 6 7 8 9] [10 11 12 13]] ‘‘‘ a_arg_max = np.argmax(a)‘‘‘ 返回最大索引 11 ‘‘‘ mean_a = np.mean(a) ‘‘‘ mean平均值 7.5 ‘‘‘ avg_a = np.average(a) ‘‘‘ average加權平均值 7.5 ‘‘‘ mean_x = np.mean(np.array([1,2,3,4,5])) average_x = np.average(np.array([1,2,3,4,5]), weights=np.array([1,1,1,1,1])) median_a = np.median(a) ‘‘‘ median中位數 7.5 ‘‘‘ cumsum_a = np.cumsum(a) ‘‘‘ cumsum元素累加 [ 2 5 9 14 20 27 35 44 54 65 77 90]‘‘‘ diff_a = np.diff(a, axis=0) ‘‘‘ 數值差分 [[4 4 4 4] [4 4 4 4]] ‘‘‘ nonzero_a = np.nonzero(a) ‘‘‘ nonzero這個函數將所有非零元素的行與列坐標分割開，重構成兩個分別關於行和列的矩陣 (array([0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2], dtype=int64), array([0, 1, 2, 3, 0, 1, 2, 3, 0, 1, 2, 3], dtype=int64)) ‘‘‘ sort_a = np.sort(a,axis=-1,kind=‘mergesort‘) transpose_a= np.transpose(a) transpose_a_2 = a.T ‘‘‘ 矩陣的轉置 transpose ‘‘‘ clip_a = np.clip(a,5,9) ‘‘‘ clip指定的元素轉換為最小值或者最大值 [[5 5 5 5] [6 7 8 9] [9 9 9 9]] ‘‘‘
Numpy 基礎運算2