It is a well-known fact that Python is one of the most popular programming languages for data mining and Web Scraping. There are tons of libraries and niche scrapers around the community, but we’d like to share the 5 most popular of them.
Scrapy is a fast high-level web crawling and web scraping framework, used to crawl websites and extract structured data from their pages. It can be used for a wide range of purposes, from data mining to monitoring and automated testing. Nov 05, 2018 Web Scraping with Python Code Samples. These code samples are for the book Web Scraping with Python 2nd Edition. If you're looking for the first edition code files, they can be found in the v1 directory. Most code for the second edition is contained in Jupyter notebooks. Although these files can be viewed directly in your browser in Github. Scraping the web in python. We have just scraped HTML data from the web. You have done so using 2 different packages: urllib and requests.You also saw that requests provided a higher-level interface, i.e, you needed to write a fewer lines of code to retrieve the relevant HTML as a string. HTML is a mix of unstructured and structed data.
Most of these libraries' advantages can be received by using our API and some of these libraries can be used in stack with it.
Well known library for most of the Python developers as a fundamental tool to get raw HTML data from web resources.
To install the library just execute the following PyPI command in your command prompt or Terminal:
After this you can check installation using REPL:
When we’re talking about the speed and parsing of the HTML we should keep in mind this great library called LXML. This is a real champion in HTML and XML parsing while Web Scraping, so the software based on LXML can be used for scraping of frequently-changing pages like gambling sites that provide odds for live events.
To install the library just execute the following PyPI command in your command prompt or Terminal:
The LXML Toolkit is a really powerful instrument and the whole functionality can’t be described in just a few words, so the following links might be very useful:
Probably 80% of all the Python Web Scraping tutorials on the Internet uses the BeautifulSoup4 library as a simple tool for dealing with retrieved HTML in the most human-preferable way. Selectors, attributes, DOM-tree, and much more. The perfect choice for porting code to or from Javascript's Cheerio or jQuery.
To install this library just execute the following PyPI command in your command prompt or Terminal:
As it was mentioned before, there are a bunch of tutorials around the Internet about BeautifulSoup4 usage, so do not hesitate to Google it!
Selenium is the most popular Web Driver that has a lot of wrappers suitable for most programming languages. Quality Assurance engineers, automation specialists, developers, data scientists - all of them at least once used this perfect tool. For the Web Scraping it’s like a Swiss Army knife - there are no additional libraries needed because any action can be performed with a browser like a real user: page opening, button click, form filling, Captcha resolving, and much more.
To install this library just execute the following PyPI command in your command prompt or Terminal:
The code below describes how easy Web Crawling can be started with using Selenium:
As this example only illustrates 1% of the Selenium power, we’d like to offer of following useful links:
Scrapy is the greatest Web Scraping framework, and it was developed by a team with a lot of enterprise scraping experience. The software created on top of this library can be a crawler, scraper, and data extractor or even all this together.
To install this library just execute the following PyPI command in your command prompt or Terminal:
We definitely suggest you start with a tutorial to know more about this piece of gold: https://docs.scrapy.org/en/latest/intro/tutorial.html
As usual, the useful links are below:
So, it’s all up to you and up to the task you’re trying to resolve, but always remember to read the Privacy Policy and Terms of the site you’re scraping 😉.
Before reading it, please read the warnings in my blog Learning Python: Web Scraping.
Scrapy is an application framework for crawling web sites and extracting structured data which can be used for a wide range of useful applications, like data mining, information processing or historical archival.You can install Scrapy via pip
.
Don’t use the python-scrapy package provided by Ubuntu, they are typically too old and slow to catch up with latest Scrapy.Instead, use pip install scrapy
to install.
After installation, try python3 -m scrapy --help
and get help information:
A basic flow of Scrapy usage:
Create a new Scrapy project:
Then it will create a directory like:
Create a class of our own spider which is the subclass of scrapy.Spider
in the file soccer_spider.py
under the soccer/spiders
directory.
name
: identifies the Spider. It must be unique within a project.start_requests()
: must return an iterable of Requests which the Spider will begin to crawl from.parse()
: a method that will be called to handle the response downloaded for each of the requests made.scrapy.Request
objects returned by the start_requests
method of the Spider.Go to the soccer
root directory and run the spider using runspider
or crawl
commands:
When getting the page content in response.body
or in a local saved file, you could use other libraries such as Beautiful Soup to parse it.Here, I will continue use the methods provided by Scrapy to parse the content.
Scrapy provides CSS selectors .css()
and XPath .xpath()
for the response
object. Some examples:
With that, you can extract the data according to the elements, CSS styles or XPath. Add the codes in the parse()
method.
Sometimes, you may want to extract the data from another link in the page.Then you can find the link and get the response by sending another request like:
Use the .urljoin()
method to build a full absolute URL (since sometimes the links can be relative).
Scrapy also provides another method .follow()
that supports relative URLs directly.
I will still use the data in UEFA European Cup Matches 2017/2018 as an example.
The HTML content in the page looks like:
I developed a new class extends the scrapy.Spider
class and then run it via Scrapy to extract the data.
I prefer using XPath because it is more flexible.Learn more about XPath in XML and XPath in W3Schools or other tutorials.
You can use other shell commands such as python3 -m scrapy shell 'URL'
to do some testing job before writing your own spider.
More information about Scrapy in detail can be found in Scrapy Official Documentation or its GitHub.