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The examples in this article describe how Python uses BS4 to get the 58 city classification of cities. Share to everyone for your reference. Specific as follows:
#-*-Coding:utf-8-*-#! /usr/bin/pythonimport urllibimport OS, datetime, Sysfrom BS4 import beautifulsoupreload (SYS) sys.setdefaultencoding (" Utf-8 ") __baseurl__ =" http://bj.58.com/"__initurl__ =" http://bj.58.com/hezu/"Soup=beautifulsoup (Urll
First, the memory modelClassification of variables based on their organization in memoryThe type of Python, like most other languages, can hold one or more values. A type that can hold a single literal object we call it atomic or scalar storage , those types that can hold multiple objects, which we call container storage . (Container objects are sometimes referred to as compound objects in a document, but they do not just refer to types, but also incl
The example of this article describes the Python-based urllib implementation according to Baidu Music classification download mp3 method. Share to everyone for your reference. The implementation method is as follows:
#!/usr/bin/env python#-*-coding:utf-8-*-import urllibimport rebaseurl = "http://music.baidu.com" url = "http// music.baidu.com/search/tag?key= Cla
the category name fileprob= net.blobs['prob'].data[0].flatten ()#Take out the last layer (prob) belongs to the probability value of a category and print, ' prob ' is the name of the last layer PrintProb Order=prob.argsort () [999]#sort the probability value, take out the maximum value of the ordinal, 9 refers to the classification of 90 refers to the number of classes in the deploy file; #the Argsort () function is arranged from small to large
1. Confusion Matrixis a confusion matrix of two types of problems in which the output uses a different category labelCommonly used metrics to measure classification performance are:
The correct rate (Precision), which is equal to tp/(TP+FP), gives the ratio of the true positive example in the sample that is predicted to be a positive example.
recall Rate (Recall), which he equals to tp/(TP+FN), gives the true positive example of the predi
This article describes the Python based on urllib implementation of Baidu Music classification download mp3 method. Share to everyone for your reference. The implementation methods are as follows:
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#!/usr/bin/env python #-*-coding:utf-8-*-import urllib import re baseurl = "http://music.baidu.com"
(Python) (supervised) kNN-Nearest Neighbor Classification Algorithm
Supervised kNN neighbor algorithms:
(1) calculate the distance between a point and the current point in a dataset of known classes.
(2) sort by ascending distance
(3) Select k points with the minimum distance from the current point
(4) determine the frequency of occurrence of the category of the first k points
(5) return the category with t
This article introduces the content of the detailed classification evaluation indicators and regression evaluation indicators and Python code implementation, has a certain reference value, now share to everyone, there is a need for friends to refer to.
1. Concept
Performance measurement (evaluation) indicators, the main divided into two major categories:1) Classificatio
classifiersPlt.figure (facecolor= ' W ')Plt.pcolormesh (x1, x2, Y_hat, Cmap=cm_light) # Display of predictive values(5) Show classification effect of classifier (add sample points)Plt.scatter (x[:, 0], x[:, 1], s=30, c=y, edgecolors= ' K ', cmap=cm_light) # sample DisplaySummarize:Draw the classification interface of the classifier first, form the grid data with Np.meshgrid (), then draw with the help of P
Today read the Python language written using SMO in SVM optimization, using the RBF function for handwriting recognition, the following simple collation of the whole process and ideas, and then detailed the various parts.(1) Acquiring training data sets Trainingmat and Labelmat;(2) Optimization parameters Alphas and B are optimized using SMO, this step is to train to obtain the optimal parameters(3) using Alphas and B into the RBF Gaussian kernel func
The first thing to understand is that crawling pages are actually:Find a list of URLs (URLs) that contain the information we needDownload the page back via the HTTP protocolParse the required information from the HTML of the pageFind out more about this URL and go back to 2 to continueSecond, we must understand:A good list should:URLs that contain enough moviesThrough the page, you can traverse all the moviesA list sorted by update time to catch the latest updated movies fasterThe final simulati
Author:headsen ChenDate:2018-03-21 17:42:13Notice:this article created by Headsen Chen himself and don't allowed to copy,or you'll count law question and to pay 10 000$!!!1, the execution of the function name is called directly:2, execution in return:The results of the implementation are as follows:3, executed in print 1: single function without parameters execution: print (f ())The results are as follows:4, executed in print 2: Higher order function with parameters: print (f (a))The results are
)#Creating a new cluster centerdefNew_dis_center (x,z_1,z_2,n1,n2): Z_1_1=[0,0] Z_2_1=[0,0] forIinchRange (0, (Len (N1))): Z_1_1=z_1_1+x[n1[i]]/Len (N1) forIinchRange (0, (Len (N2))): Z_2_1=z_2_1+x[n2[i]]/Len (n2)returnZ_1_1,z_2_1#iterate function input data and initial cluster centerdefIteration_fun (x,z_1,z_2):#Initialize the intermediate amount of the iterative cluster centerz_1_1=[0,0] Z_2_1=[0,0] N1=[] N2=[] Distribution (X,Z_1,Z_2,N1,N2) (z_1_1,z_2_1)=New_dis_center (X,Z_1,Z_2,N1,N2)#Itera
, y_pred, beta[, labels, ...])
Hamming_loss (Y_true, y_pred[, classes])
Jaccard_similarity_score (Y_true, y_pred[, ...])
Log_loss (Y_true, y_pred[, EPS, normalize, ...])
Precision_recall_fscore_support (Y_true, y_pred)
Precision_score (Y_true, y_pred[, labels, ...])
Recall_score (Y_true, y_pred[, labels, ...])
Zero_one_loss (Y_true, y_pred[, normalize, ...])
There are also some issues that can be used for both two-label and multi-label (not multi-
Small task: Achieve picture classification1. Picture materialPython bulk compress jpg images: PiL library resizehttp://blog.csdn.net/u012234115/article/details/502484092. Environment ConstructionInstallation version of Python under Windows comparison 2.7 vs 3.6Https://pypi.python.org/pypiInstallation of the PIL Library under WindowsHttps://pypi.python.org/pypiInstallation of the PIL Library under Windowshttp://zjfsharp.iteye.com/blog/2311523Installati
AssertionError异常将执行except下面的代码块 print ("AThe above example output is aExample 2: Catching exceptions using multiple except#!/usr/bin/python#coding:utf8#try is used in conjunction with multiple except to execute sequentially in a try code block, as long as an exception is caught to stop execution A = 1b = 2c = "1" Try:assert a The above results are unsupported operand type (s) for +: ' int ' and ' str ' do not support integral type and string type addi
A supervised KNN neighbor algorithm:(1) Calculate the distance between the points in a well-known category dataset and the current point(2) Sorting in ascending order of distance(3) Select K points with a minimum distance from the current point(4) Determine the frequency of the category in which the first K points are present(5) Return to the category with the highest frequency of the first K points as the forecast classification of the current point#
There are four main parameters for defining methods in Python:1. General Parameters:Common parameters are very common.def F1 (name, age): Print('My name is%s, I am%s yearsold' % (name, age))Name and age are two common parameters. When calling method F1, be sure to pass in the name and age two arguments in the order in which they were defined.F1 ('Andy', 21)2. Default parameters:The default parameter refers to a default value in the definition meth
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