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python 判斷矩陣中每行非零個(gè)數(shù)的方法

發(fā)布時(shí)間:2020-10-07 16:11:27 來(lái)源:腳本之家 閱讀:152 作者:四座 欄目:開(kāi)發(fā)技術(shù)

如下所示:

# -*- coding: utf-8 -*-
# @Time  : 2018/5/17 15:05
# @Author : Sizer
# @Site  : 
# @File  : test.py
# @Software: PyCharm
import time
import numpy as np

# data = np.array([
# [5.0, 3.0, 4.0, 4.0, 0.0],
# [3.0, 1.0, 2.0, 3.0, 3.0],
# [4.0, 3.0, 4.0, 3.0, 5.0],
# [3.0, 3.0, 1.0, 5.0, 4.0],
# [1.0, 5.0, 5.0, 2.0, 1.0]
# ])
data = np.random.random((1000, 1000))
print(data.shape)
start_time = time.time()
# avg = [float(np.mean(data[i, :])) for i in range(data.shape[0])]
# print(avg)


start_time = time.time()
avg = []
for i in range(data.shape[0]):
  sum = 0
  cnt = 0
  for rx in data[i, :]:
   if rx > 0:
     sum += rx
     cnt += 1
  if cnt > 0:
   avg.append(sum/cnt)
  else:
   avg.append(0)
end_time = time.time()
print("op 1:", end_time - start_time)

start_time = time.time()
avg = []
isexist = (data > 0) * 1
for i in range(data.shape[0]):
  sum = np.dot(data[i, :], isexist[i, :])
  cnt = np.sum(isexist[i, :])
  if cnt > 0:
   avg.append(sum / cnt)
  else:
   avg.append(0)
end_time = time.time()
print("op 2:", end_time - start_time)
#
# print(avg)
factor = np.mat(np.ones(data.shape[1])).T
# print("facotr :")
# print(factor)
exist = np.mat((data > 0) * 1.0)
# print("exist :")
# print(exist)
# print("res  :")
res = np.array(exist * factor)
end_time = time.time()
print("op 3:", end_time-start_time)

start_time = time.time()
exist = (data > 0) * 1.0
factor = np.ones(data.shape[1])
res = np.dot(exist, factor)
end_time = time.time()
print("op 4:", end_time - start_time)

經(jīng)過(guò)多次驗(yàn)證, 第四種實(shí)現(xiàn)方式的事件效率最高!

以上這篇python 判斷矩陣中每行非零個(gè)數(shù)的方法就是小編分享給大家的全部?jī)?nèi)容了,希望能給大家一個(gè)參考,也希望大家多多支持億速云。

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