python xpath example

We all know that the basic usage of else in Python is the if...elif...else in the conditional control statement ..., but else there are two other uses, one for the end of the loop and the other for the error-handling try. This was originally the standard syntax for Python, but because of the different habits of most other programming languages, people intentionally or unintentionally ignored these usages. I

Python slice usage example tutorial, This article describes how to use the slice operation in Python in the form of an example and shares it with you for your reference. The details are as follows: It is very common to retrieve some elements of a list or tuple. For example,

Example of how to use a function (closure) in a Python function. This example describes how to use the Python closure. We will share this with you for your reference. The details are as follows: You can also define functions, that is, closures, in Python functions. Similar t

The following is an example of how to use Python to call the System Shell in Linux. You need to directly call Shell commands to complete some simple operations, such as mount a file system. So how can we use Python to call Linux Shell commands? The following describes several common methods:1. OS Module 1.1. exec method family of OS ModuleThe exec System Method o

resaon attribute containing the error code and error message. The following code is used to test the effect; import urllib import urllib2 url = 'http://www.server.com/register.php' user_agent = 'Mozilla/5.0 (Windows NT 6.1; rv:33.0) Gecko/20100101 Firefox/33.0' values = {'useid' : 'user', 'pwd' : '***', 'language' : 'Python' } headers = { 'User-Agent' : user_agent } data = urllib.urlencode(values) req = urllib2.Request(url, data, headers) r

functions are written to test the inheritance and polymorphism of classes in Python#Write a animal class, which has a run methodclassAnimal (object):defRun (self):Print "Animal is running ..."#write a cat and dog class inheriting from the animal classclassCat (Animal):defRun (self):Print "Cat is running ..." defEat (self):Print "Cat is eating ..."classDog (Animal):defRun (self):Print "Dog is running ..." defEat (self):Print "Dog is eating ..."t

As we all know, Python's parallel processing capability is not ideal. I think that if we don't consider the standard parameters of threads and Gil (most of them are legitimate), the reason is not that the technology is not in place, but that we are not using the appropriate method. Most of the textbooks on Python threads and multiple processes are excellent, but the content is tedious. They do have a lot of useful information at the beginning, but oft

Example of how to read and write csv files using Python, This example describes how to read and write csv files in Python. We will share this with you for your reference. The details are as follows: Create a csvdata.csv file with the following data: The Code is as follows: # Coding: utf-8import csv # Read csv file met

Python optionParser module usage example tutorial, pythonoptionparser This article describes how to use the optionParser module in Python in detail in the form of examples. It is of great reference value for deep learning Python. Share it with you for your reference. The specific analysis is as follows: In general,

This example describes the use of Python under MySQLdb. Share to everyone for your reference. The specific analysis is as follows: Download and install MySQLdb ①linux version http://sourceforge.net/projects/mysql-python/download, in the installation is to first install Setuptools, and then in the download file directory, modify Mysite.cfg, Specify the path to th

Hexadecimal encoding is also a common encoding solution in web applications. As a web security engineer, we are aware that MySQL injection can be bypassed using hex.htmlspecialchars()Function to write data to webshell. For example: select 0x3c3f70687020406576616c28245f504f53545b615d293b203f3e into outfile '/web/1.php' The following describes how to implement hex encryption and decryption in python: >>> '

Example Analysis of range () function usage in python development, pythonrange This article describes the usage of the range () function in python development. We will share this with you for your reference. The details are as follows: The range () function in python is very powerful, so I think it is necessary to shar

Python keyword module usage Example Analysis, pythonkeyword This example describes how to use the python keyword module. Share it with you for your reference. The details are as follows: Help on module keyword:NAME keyword - Keywords (from "graminit.c")FILE /usr/lib64/python2.6/keyword.pyDESCRIPTION This file is aut

The decorator contains a lot of advanced Python skills, and @ property is no exception. for example, an example of rapid code refactoring will be mentioned later, here we will illustrate the usage of @ property decorators in Python programming with examples: Value and value assignment class Actress(): def __init__(s

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

For example, we will introduce 25 hidden features in Python and the python25 feature. Note: well-known techniques such as generator, decorator, and switch variable are ignored.1. function parameter unpack This is a common story: def foo(x, y): print x, y alist = [1, 2]adict = {'x': 1, 'y': 2} foo(*alist) # 1, 2foo(**adict) # 1, 2 2. chained comparison Operators >>> x = 3>>> 1 3. Pay attention to the defau

The example in this article tells the list initialization method in Python. Share to everyone for your reference, specific as follows: 1, the basic method. LST = [1, 2, 3, 4, 5] 2. Initialize consecutive digits. >>> LST = [n for n in range (5)] >>> print (LST) [5, 6, 7, 8, 9] 3, initialize n the same value. (Two ways) >>> LST = [' x ' for n in range (5)] >>> print (LST

independent.As an example of a Debian Linux installation (although I use it on Windows): Copy the Code code as follows: sudo apt-get install python-numpy python-scipy python-matplotlib ipython ipython-notebook python-pandas python