python top k问题

numpy的：

  

   

    

     

    
    

     

      import numpy as np
     
    
   

    

     

    
    

     

      top_k=3
     
    
   

    

     

    
    

     

      arr = np.array([1, 3, 2, 4, 5])
     
    
   

    

     

    
    

     

      top_k_idx=arr.argsort()[::-1][0:top_k]
     
    
   

    

     

    
    

     

      print(top_k_idx)
     
    
  
 

  

   

    

     

    
    

     

      #coding=utf-8
     
    
   

    

     

    
    

     

      '''
     
    
   

    

     

    
    

     

      Created on Sep 21, 2015
     
    
   

    

     

    
    

     

      @author: haoyifen
     
    
   

    

     

    
    

     

      '''
     
    
   

    

     

    
    

     

      import time
     
    
   

    

     

    
    

     

      import random
     
    
   

    

     

    
    

     

      def left(i):
     
    
   

    

     

    
    

     
  return 2*i+1
     
    
   

    

     

    
    

     

      def right(i):
     
    
   

    

     

    
    

     
  return 2*i+2
     
    
   

    

     

    
    

     

      def min_heapify(a,heap_size,i):
     
    
   

    

     

    
    

     

        l=left(i)
     
    
   

    

     

    
    

     

        r=right(i)
     
    
   

    

     

    
    

     
  if l<heap_size and a[l]<a[i] :
     
    
   

    

     

    
    

     

       least=l
     
    
   

    

     

    
    

     
  else:
     
    
   

    

     

    
    

     

       least=i
     
    
   

    

     

    
    

     
  if r<heap_size and a[r]<a[least]:
     
    
   

    

     

    
    

     

       least=r
     
    
   

    

     

    
    

     
  if least!=i:
     
    
   

    

     

    
    

     

       a[i],a[least]=a[least],a[i]
     
    
   

    

     

    
    

     

       min_heapify(a, heap_size, least)
     
    
   

    

     

    
    

     

      def build_min_heap(a,heap_size):
     
    
   

    

     

    
    

     
  for i in range((heap_size-1)//2,-1,-1):
     
    
   

    

     

    
    

     

       min_heapify(a, heap_size, i)
     
    
   

    

     

    
    

     

      def heap_sort(a,heap_size):
     
    
   

    

     

    
    

     

        build_min_heap(a, heap_size)
     
    
   

    

     

    
    

     
  for i in range(heap_size-1,0,-1):
     
    
   

    

     

    
    

     

       a[i],a[0]=a[0],a[i]
     
    
   

    

     

    
    

     
 #print a
     
    
   

    

     

    
    

     

       heap_size-=1
     
    
   

    

     

    
    

     

       min_heapify(a, hea
     
    
  
 

文章来源: blog.csdn.net，作者：网奇，版权归原作者所有，如需转载，请联系作者。

原文链接：blog.csdn.net/jacke121/article/details/88933119