What foundation is needed for python crawler-Python Tutorial-php.cn

Home

Backend Development

Python Tutorial

What foundation is needed for python crawler

silencement

May 17, 2019 pm 08:03 PM

Starting with a crawler does not require you to be proficient in Python programming, but basic knowledge cannot be ignored. So what Python basics do we need?
What foundation is needed for python crawler

First of all, let’s take a look at the simplest crawler process:

What foundation is needed for python crawler

The first step To Determine the link of the crawled page. Since we usually crawl more than one page of content, we should pay attention to the change of the link when the page is turned and the keyword changes. Sometimes we even need to consider the date; in addition, the main web page needs to be static, Dynamically loaded.

The second step Request resources, this is not difficult, mainly the use of Urllib and Request libraries, just read the official documents when necessary

The third step is to parse the web page. After the resource request is successful, the source code of the entire web page is returned. At this time, we need to locate and clean the data

When it comes to data, the first point to pay attention to is the type of data. Should you master it?

Secondly, the data on the web page is often arranged very neatly, thanks to the list. Most web page data is neat and regular, so do you need to master lists and loop statements too!

But it is worth noting that the web page data is not necessarily neat and regular. For example, the most common personal information, except for the required options, I don’t like to fill in other parts. At this time, some information is missing. You have to first determine whether there is data before crawling, so the judgment statement cannot be less!

After mastering the above content, our crawler can basically run, but in order to improve the code efficiency, we can use functions to divide a program into multiple small parts, each part is responsible for a part of the content, so that we can You need to mobilize a function multiple times. If you are more powerful and develop a crawler software in the future, do you need to master another class?

The fourth step is to save the data, is it necessary? First open the file, write data, and finally close it, so do you still need to master the reading and writing of files?

So, The most basic Python knowledge points you need to master are:

What foundation is needed for python crawler

#So, if you want to learn crawling, you can get twice the result with half the effort only by mastering the above Python-related knowledge.

The above is the detailed content of What foundation is needed for python crawler. For more information, please follow other related articles on the PHP Chinese website!

Statement

The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Learning Python: Is 2 Hours of Daily Study Sufficient?Apr 18, 2025 am 12:22 AM

Is it enough to learn Python for two hours a day? It depends on your goals and learning methods. 1) Develop a clear learning plan, 2) Select appropriate learning resources and methods, 3) Practice and review and consolidate hands-on practice and review and consolidate, and you can gradually master the basic knowledge and advanced functions of Python during this period.

Python for Web Development: Key ApplicationsApr 18, 2025 am 12:20 AM

Key applications of Python in web development include the use of Django and Flask frameworks, API development, data analysis and visualization, machine learning and AI, and performance optimization. 1. Django and Flask framework: Django is suitable for rapid development of complex applications, and Flask is suitable for small or highly customized projects. 2. API development: Use Flask or DjangoRESTFramework to build RESTfulAPI. 3. Data analysis and visualization: Use Python to process data and display it through the web interface. 4. Machine Learning and AI: Python is used to build intelligent web applications. 5. Performance optimization: optimized through asynchronous programming, caching and code

Python vs. C : Exploring Performance and EfficiencyApr 18, 2025 am 12:20 AM

Python is better than C in development efficiency, but C is higher in execution performance. 1. Python's concise syntax and rich libraries improve development efficiency. 2.C's compilation-type characteristics and hardware control improve execution performance. When making a choice, you need to weigh the development speed and execution efficiency based on project needs.

Python in Action: Real-World ExamplesApr 18, 2025 am 12:18 AM

Python's real-world applications include data analytics, web development, artificial intelligence and automation. 1) In data analysis, Python uses Pandas and Matplotlib to process and visualize data. 2) In web development, Django and Flask frameworks simplify the creation of web applications. 3) In the field of artificial intelligence, TensorFlow and PyTorch are used to build and train models. 4) In terms of automation, Python scripts can be used for tasks such as copying files.

Python's Main Uses: A Comprehensive OverviewApr 18, 2025 am 12:18 AM

Python is widely used in data science, web development and automation scripting fields. 1) In data science, Python simplifies data processing and analysis through libraries such as NumPy and Pandas. 2) In web development, the Django and Flask frameworks enable developers to quickly build applications. 3) In automated scripts, Python's simplicity and standard library make it ideal.

The Main Purpose of Python: Flexibility and Ease of UseApr 17, 2025 am 12:14 AM

Python's flexibility is reflected in multi-paradigm support and dynamic type systems, while ease of use comes from a simple syntax and rich standard library. 1. Flexibility: Supports object-oriented, functional and procedural programming, and dynamic type systems improve development efficiency. 2. Ease of use: The grammar is close to natural language, the standard library covers a wide range of functions, and simplifies the development process.

Python: The Power of Versatile ProgrammingApr 17, 2025 am 12:09 AM

Python is highly favored for its simplicity and power, suitable for all needs from beginners to advanced developers. Its versatility is reflected in: 1) Easy to learn and use, simple syntax; 2) Rich libraries and frameworks, such as NumPy, Pandas, etc.; 3) Cross-platform support, which can be run on a variety of operating systems; 4) Suitable for scripting and automation tasks to improve work efficiency.

Learning Python in 2 Hours a Day: A Practical GuideApr 17, 2025 am 12:05 AM

Yes, learn Python in two hours a day. 1. Develop a reasonable study plan, 2. Select the right learning resources, 3. Consolidate the knowledge learned through practice. These steps can help you master Python in a short time.

See all articles