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Python 如何找到一个巨大csv文件的最大10个值?_Python_Algorithm_Image Processing_Minmax - Fatal编程技术网

Python 如何找到一个巨大csv文件的最大10个值?

Python 如何找到一个巨大csv文件的最大10个值?,python,algorithm,image-processing,minmax,Python,Algorithm,Image Processing,Minmax,我试图找到Harris算法作为输出给出的.csv文件的最大10个值。你能帮我吗?我想办法找到最大值,但不是先找到10 import cv2 import numpy as np from numpy import genfromtxt filename = 'boy.jpg' img = cv2.imread(filename) gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY) gray = np.float32(gray) dst = cv2.co

我试图找到Harris算法作为输出给出的.csv文件的最大10个值。你能帮我吗?我想办法找到最大值,但不是先找到10

import cv2
import numpy as np
from numpy import genfromtxt

filename = 'boy.jpg'

img = cv2.imread(filename)
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)

gray = np.float32(gray)
dst = cv2.cornerHarris(gray, 2, 3, 0.04)

# result is dilated for making the corners, not important
dst = cv2.dilate(dst, None)

# Threshold for an optional value, it may vary depending on the image.
img[dst > 0.01 * dst.max()] = [0, 0, 255]

cv2.imshow('dst', img)

np.savetxt("data2.csv", dst, delimiter=",")

if cv2.waitKey(0) & 0xff == 27:
    cv2.destroyAllWindows()

import numpy
data1 = numpy.genfromtxt("data2.csv",dtype='float',delimiter =',', skip_header=0, skip_footer=0,usecols=11,usemask=True)
#print data1
print(data1.min())
print(data1.max())

按列对数据帧进行排序,然后打印出前10个

df.sort_values('some_column', ascending=False)[:10]

在这个网站上,有很多方法可以找到数据集中N个最大值。通常,您会进行排序,然后从中获取最大值。我被你的帖子弄糊涂了,因为你的大部分代码似乎与处理CSV文件中的值无关。它不能按列排序,因为如果你在excel中打开特定文件,除非它很大,否则它不会显示正确的值。只有在pycharm.df中打开.csv文件时,才会显示正确的值。columns将生成数据帧的列名。我假设Harris算法的值是您想要排序的列。使用此列名对值进行排序:df.sort_values'Harris_alg',升序=False[:10]