Examples of Sklearn dimensionality reduction methods
importing related packages with datasets.digits data as an example
Import NumPy as NP
import pandas as PD
import matplotlib.pyplot as Plt
import time from
sklearn.datasets I Mport Load_digits
Visualization of large sample data is a relatively troublesome thing,
In general, we will use the dimensionality reduction method to deal with the characteristics first. Let's look at an example to see what
The K-fold verification proposed in this paper is the Stratifiedkfold method in the Sklearn package in Python.The idea of the method is described: http://scikit-learn.org/stable/modules/cross_validation.htmlStratifiedkfold Is a variation of K-fold which returns stratified Folds:each set contains approximately the same percentage of samples of each target class as the complete set.TranslationStratifiedkfold is the one that sets each sample in the data
"" "Function: Logical regression Description: Author: Tang Tianze Blog: http://blog.csdn.net/u010837794/article/details/Date: 2017-08-14" "," "Import the package required for the project" "" Imports Nump Y as NP import matplotlib.pyplot as PLT # using Cross-validation method, the dataset is divided into training set test set from sklearn.model_selection import Train_test_split F Rom sklearn import datasets from Sklearn.linear_model import logisticre
When using Python's machine learning package Sklearn, if the training set is fixed, we often want to save the results of a trained model for the next use, which avoids the hassle of retraining the model every time it runs.In Python, there is a joblib that can save the model and take the saved model out for different sets of tests:1 fromSklearnImportSVM2 fromSklearn.externalsImportJoblib3 4 #Training Model5CLF = Svc = SVM. SVC (kernel='Linear')6rf=Cl
The Sklearn module provides a solution to the decision tree without having to build the wheel yourself (it will not be made, it feels slightly complicated):Here are the notes:Introduction of Sklearn.tree parameters and suggestions for use of recommended parametersOfficial website: http://scikit-learn.org/stable/modules/generated/sklearn.tree.DecisionTreeClassifier.html class Sklearn.tree.DecisionTreeClassifier (criterion= ' Gini ', splitter= ' best ',
First, attach the official website description[Http://scikit-learn.org/stable/modules/generated/sklearn.cluster.KMeans.html#examples-using-sklearn-cluster-kmeans]Attach a translation documenthttp://blog.csdn.net/xiaoyi_zhang/article/details/52269242Another example of Baidu search (infringement delete):#-*-Coding:utf-8-*-From Sklearn.clusterImport KmeansFrom Sklearn.externalsImport JoblibImport numpyfinal = open (' C:/test/final.dat ',' r ') data = [Li
Original source: http://www.cnblogs.com/pinard/p/6035872.html, on the basis of the original made a number of amendmentsThe Logisticregression API in Sklearn is as follows, official documentation: Http://scikit-learn.org/stable/modules/generated/sklearn.linear_model. Linearregression.html#sklearn.linear_model. Linearregression
Class Sklearn.linear_model. Logisticregression (penalty= ' L2 ', Dual=false, tol=0.0001, c=1.0, Fit_intercept=true, Intercept_s
The server needs to have a python environment, as well as a Python-run dependency package, and Java communicates with Python using process processes.Installing homebrew/usr/bin/ruby-e "$ (curl-fssl https://raw.githubusercontent.com/Homebrew/install/master/install)"Installing Python3 with HomebrewThe Brew install Python3 will automatically configure the environment variable installation complete can be which python3 to find the location of the installed Python3Python version switchingln–s/usr/loc
There are three functions in the use of PCA and NFC fit,fit_transform,transform distinguish between their respective functions. Pass the test, barely understand their differences, and make some notes here.1.fit_transform is a blend of fit and transform, which is equivalent to calling fit before calling transform.The 2.transform function must be called after the Fit function or an error will be3.fit_transform returns the result of a reduced dimension, and is a column-compressedThe 4.fit function
number of samples as a percentage of the total number of samples. If the sample size is small, you do not need to tube this value. If the sample quantity is very large, it is recommended to increase this value. 5) Minimum sample weights and min_weight_fraction_leaf for leaf nodes : This value limits the minimum value of all sample weights and the leaf node, and if it is less than this value, it is pruned along with the sibling nodes. The default is 0, which is to not consider the weight issue.
1. Linear regression:
Import pandas as PD
import NumPy as NP
from Sklearn import Linear_model as LM
#准备数据, the Fit function requires X to be a matrix, and the y term is a sequence, so only a single Variable needs to be transpose
A=pd.read_excel (R ' D:\baidu\Desktop\1.xls ')
b=a.icol (1)
b=[[x] for x in B] #或者b =b.reshape (len (b) , 1)
C=a.icol (2)
#训练模型
f=lm. Linearregression ()
f1=f.fit (b,c)
#获得结果
c,i,p=f1.coef_,f1.intercept_,f1.predict #f1.
In modular learning, there are generally parametric learning_rate: Learning rate Learning Rate
This is a value on [0, 1], and some of the articles say it's used to set the iteration range in the algorithm,
The General Assembly leads to the fitting, the fitting means that the fitting function oscillation instability, which is intuitively understandable.
For the AdaBoost combined model call Staged_predict, the predicted values for each iteration stage can be obtained.
The Sklearn.metrics.zero_one_
N-gram
The TF and IDF formulas here are the formulas used by TFIDF in Sklearn. And the original formula will have some discrepancy. And varies according to some parameters.
Explanation of the noun:Corpus: Refers to the collection of all documentsDocuments: The orderly arrangement of words. It can be an article, a sentence or something. Word frequency (TF)
In a given document, the word frequency (term FREQUENCY,TF) refers to how often a given term a
Logistic regression is a kind of classification algorithm, which can be used to predict the probability of event occurrence, or the probability that something belongs to a certain class. Logical regression is based on the logistic function, and the value of the function is between 0~1 and the probability value.1.k-Fold Cross ValidationDivide the DataSet into K-parts, and during the K iterations, each package is used for validation 1 times and the remainder is used for training. Example:
KF = Kfo
:
x_ Train, X_test = Train.values[train_index], Train.values[test_index]
y_train, y_test = Labels[train_index], labels[ Test_index]
Sklearn Classifier Showdown
Simply Looping through out-of-the box classifiers and printing the results. Obviously, these would perform much better after tuning their hyperparameters, but this gives you a decent ballpark idea. In [4]:
From sklearn.metrics import Accuracy_score, log_loss from sklearn.neighbors im
about installing the configuration Numpy,scipy,matplotlibm,pandas and Sklearn under Ubuntu
The most recent learning machine in Python is the need to configure related components. Also checked on the Internet some, summed up a bit. By the way, if there is any mistake, please point out, thank you.Recommended links to configuration and corresponding installation packages in Windows environment you can take a look.
My system environment is ubuntu14.04lts
Prerequisite environment (according to the installation of the subject):python3.7Windows10First of all, to download the three kinds of packages for https://www.lfd.uci.edu/~gohlke/pythonlibs/(if you want to download other packages, you can find and then the next), the download should be aware that you must first download a good NumPy package, Download the Scipy,sklearn package in turn, and note that the download and your Python, computer corresponding
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