principal component analysis example python

This example describes the Super keyword usage in python. Share to everyone for your reference. The specific analysis is as follows: In the Python class method, you call a method of the parent class, which, before Python 2.2, is typically written like code Snippet 1: Code

This example describes the use of the Threading module join function in Python. Share to everyone for your reference. The specific analysis is as follows: Join is known to block the process until the thread is finished executing. It is common practice for us to start a batch of threads and finally join these threads to end, for

This example describes the Python ordering method. Share to everyone for your reference. Specific as follows: >>> def my_key1 (x): ... return x% 10...>>> alist = [4, 5, 8, 1, 8]>>> alist[4, 5, 8, 1,, 8]>>> Alist.sort () # Silent Ascending sort >>> alist[1, 4, 5, 8, 8, 63]>>> alist.sort (reverse = True) # change to descending sort >>> alist[63, 8, 8, 5, 4, 1]>>> alist.sort (key = my_key1) # Set the sort

signature will be executed in error.Python's built-in Functools.wraps can accomplish this task, so a complete decorator is written as follows:import functoolsdef timer(func): @functools.wraps(func) def wrapper(*args, **kwargs): start_time = time.time() res = func(*args, **kwargs) end_time = time.time() print("Run time is: %s" % (end_time - start_time)) return res return wrapperThe overall code is as follows:__Author__ = "Lance#"# -*- coding = utf-8 -*

The examples in this article describe references and replication usage in Python. Share to everyone for your reference. The specific analysis is as follows: In Python, any immutable object is a value, and a Mutable object is a reference. Immutable objects (such as integers, strings) are actually copied, whether they are passing arguments to a function or any fo

The example in this article describes the Python custom master-slave distributed architecture. Share to everyone for your reference, specific as follows: Environment: Win7 X64,python 2.7,apscheduler 2.1.2. The schematic diagram is as follows: Code section: (1), center node: #encoding =utf-8 #author: Walker #date: 2014-12-03 #function: central node (mai

This example describes the global usage in Python. Share to everyone for your reference. The specific analysis is as follows: 1. Global---Define variables as globals. You can change the value of a variable within a function by defining it as a global variable. 2. A global statement can define multiple variables at the same time, such as Global X, Y, Z Sample

This example describes the use of enumerate functions in Python. Share to everyone for your reference. The specific analysis is as follows: A new function enumerate was found today. This is typically done when a list or array is traversed by both the index and the element: ? 1 2 For I in range (0,len (list)): Print I, list[i] But this

The example in this article describes the Python avoid deadlock method. Share to everyone for your reference. The specific analysis is as follows: When two or more threads are waiting for resources, a deadlock occurs and two threads wait on each other. In this example, Thread1 waits for Thread2 to release block, Thre

This article mainly introduced the Python programming string correlation operation, combined with the instance form analysis Python string correlation function and the common operation skill, needs the friend to refer to the next The examples in this article describe the string-related operations of Python programming

The example in this article describes the assert usage in Python. Share to everyone for your reference. The specific analysis is as follows: 1. The Assert statement is used to declare that a condition is true. 2. If you are very confident that there is at least one element in the list you are using, and you want to test this and throw an error when it is not t

Python original string and Unicode string operator usage Example Analysis, pythonunicode This document describes the usage of the original Python string and Unicode string operators. We will share this with you for your reference. The details are as follows: # Coding = utf8''' in the original string, all strings are us

Python programming string Template usage Example Analysis, pythontemplate This document describes how to use a string Template in Python programming. We will share this with you for your reference. The details are as follows: # Coding = utf8''' string formatting operator. The programmer needs to specify the conversion

The example in this article describes threading Hyper-threading usage in Python. Share to everyone for your reference. The specific analysis is as follows: Threading Java-based threading model design. Locks (lock) and condition variables (Condition) are the basic behavior of objects in Java (each object has its own lock and condition variable), while in

This example describes the Python filter list usage. Share to everyone for your reference, as follows: Filter List [Mapping-expression for element in Source-list if filter-expression] The filter expression, which starts with an if, is any expression that returns a value of True or false (almost anything in Python). Any filter expression calculus value for an

1, >>> myteacher = ' big ' >> Yourteacher = Myteacher>> myteacher = ' small '>> Print (Yourteacher)→bigWrong answer: Myteacher 2, >>> first = 100 >> second = ' 100 '>> first = Second>> Print (first)→100Wrong answer: ' 100 ' 3, in addition to the escape, there is no way >>STR = "Let ' s go!">>print (str)→let ' s go!Double quotes and three quotation marks ("" "..." "" ") can contain single quotes, and three quotation marks (" ... ") can contain double quotes without escaping

The use of commas in type conversions is mainly the conversion of tuplesFor example:>>> a=11>>> b= (a)>>> b11>>> b= (A,)>>> b(11,)>>> b= (a,22)>>> b(11, 22)>>> b= (a,22,)>>> b(11, 22)>>>It can be seen that a comma is required to convert to a tuple type when there is only one element in the B-tupleIn addition, this multi-threaded comma is very interesting, once removed, the program will be error#coding =utf-8Import threadingFrom time import Ctime,sleep

This example describes the parameter definitions and variable parameter usages of functions in Python. Share to everyone for your reference. Specific as follows: Just learn to use Python, especially when looking at some library source code, often see Func (*args, **kwargs) Such a function definition, this * and * * is a bit confusing. In fact, as long as the fun

This paper illustrates the data transmission UDP implementation method of Python network programming. Share to everyone for your reference. The specific analysis is as follows: First, the question: Do you think that tools like msn,qq on the Web transmit data mysteriously between machines? You want to play a little bit, too? Do you pass data between the two machines? Today let

This example describes the use of the range () function in Python development. Share to everyone for your reference, as follows: The range () function in Python is very powerful, so I think it is necessary to share with you As described in its API: If you don't need to iterate through a sequence of numbers, the built-in function range () comes in handy. It gener