Posted   by 

Bs4 Cheat Sheet



Summary: To install BeautifulSoup in WIndows use the command: pip install beautifulsoup4. To install it in Linux use the command: sudo apt-get install python3-bs4.

Bs4 Cheat Sheet

Aim: In this tutorial we will discuss how to to install BeautifulSoup?

Since BeautifulSoup is not a Python standard library we need to install it before we can use it to scrape websites. Hence, we will have a look at the steps to install the BeautifulSoup 4 package (also called bs4) and also discuss some of the problems that come up after the installation.

Note: The current release is Beautiful Soup4.9.3 (October 3, 2020).

❂ Installing BeautifulSoup In Linux Machine

Bootstrap 4 Cheat Sheet & All Classes List Reference Guide. This Bootstrap 4 Cheat Sheet helps you quickly find documentation for common CSS classes, components, and grids. V4.4.1 - last updated 1/2020. Web Scraping “Web scraping (web harvesting or web data extraction) is a computer software technique of extracting information from websites.” HTML parsing is easy in Python, especially with help of the BeautifulSoup library.

❖ Platform: Debian or Ubuntu

If you are using Python in a Debian or Ubuntu-based OS, you need to install Beautiful Soup with the help of the system package manager using the following command:

✻ For Python 2.x

✻ For Python 3.x

In case you do not want to use the system package manager, you can use easy_install or pip to install bs4.

Osx high sierra update. ✻ Command to install bs4 using easy_install:

✻ Command to install bs4 using pip:

# Note: If you are using Python3, you might need to install easy_install3 or pip3 respectively before you can use them.

❖ Platform: Windows

Installing bs4 in Windows is a one step process and is very easy. Use the following command to install it using your command line interface.

❂ Some Common Problems After Installation

You might encounter an error if there’s a wrong version being installed. Download office 2008 for mac. Let us have a look at the reason behind the errors!

❖ Error: ImportError “No module named HTMLParser”

Reason: The error occurs because you are using Python 2 version of the code in Python 3.

Beautiful Soup 4 Cheatsheet | Akul's Blog

❖ Error: ImportError “No module named html.parser”

Reason: The error occurs because you are using Python 3 version of the code in Python 2.

Solution: Remove existing installation and re-install BeautifulSoup.

❖ Error: SyntaxError “Invalid syntax” on the line ROOT_TAG_NAME = u’[document]’

Solution: Convert Python 2 version of the code to Python 3 by either:

  • Installing the package −
    • python3 setup.py install
  • Manually running Python 2 to Python 3 conversion script (in the bs4 director) –
    • 2to3-3.2 -w bs4

❂ Installing The Parser

Beautiful Soup supports the HTML parser by defaultwhich is included in the Python’s standard library. However it also supports other external or third party Python parsers as shown in the table below:

Use the following commands to install the lxml or the html5lib parser,

Linux:

Windows:

Beautiful Soup - Tutorialspoint

Conclusion

With that, we come to the end of this crisp tutorial on how to install the BeautifulSoup library. Please feel free to follow the steps and install it in your system. If you want to learn how to use the BeautifulSoup library and scrape a webpage, please follow this TUTORIAL and have a look at the step by step guide to scrape your webpage.

Please subscribe and stay tuned for more interesting articles!

Where to Go From Here?

Enough theory, let’s get some practice!

To become successful in coding, you need to get out there and solve real problems for real people. That’s how you can become a six-figure earner easily. And that’s how you polish the skills you really need in practice. After all, what’s the use of learning theory that nobody ever needs?

Practice projects is how you sharpen your saw in coding!

Do you want to become a code master by focusing on practical code projects that actually earn you money and solve problems for people?

Then become a Python freelance developer! It’s the best way of approaching the task of improving your Python skills—even if you are a complete beginner.

Join my free webinar “How to Build Your High-Income Skill Python” and watch how I grew my coding business online and how you can, too—from the comfort of your own home.

I am a professional Python Blogger and Content creator. I have published numerous articles and created courses over a period of time. Presently I am working as a full-time freelancer and I have experience in domains like Python, AWS, DevOps, and Networking.

You can contact me @:

Related Posts

Summary Nox android mac. : Download a file over the web by using the following steps in Python.

  • Import libary requests
  • Define URL string
  • Get file data from URL
  • Store file data in file object on your computer

Here’s how you can do this to download the Facebook Favicon (source):

At the beginning of our struggle with web scraping, you may have trouble downloading files using Python. However, this article will provide you with several methods that you can use to download, for example, the cover of a book from the page.

As an example, we will use pages that do not prohibit scraping: http://books.toscrape.com/catalogue/category/books_1/index.html

How to Check What I’m Allowed to Scrap?

To check what exactly you are not allowed to scrap, you have to add 'robots.txt' at the end in the url of the page. It should look like this: https://www.google.com/robots.txt. If the page does not specify what can be scrapped then you should check its terms sheet.

Okay, end of the introduction, let’s get started!

How To Install Modules in Python?

Before you can use any method, you must first install the module (if you don’t have it) using:

For example:

How to Get a Link to the File?

To get a link to the file, navigate the cursor and right-click on anything you are looking for and press “Inspect Element”:

Then the source code of the page will pop up and point out immediately the element that interests us:

Next we have to copy the link to this file:

Depending on how the link looks like (whether it is full or not [if not, we have to prepare it for use]), we paste it into the search bar, to check if this is what we want:

Cached

And if it is, we use one of the methods provided.

Method 1 – requests Module

First we have to import the requests module and then create variables.

Once we have created the variables, we have to open the file in binary writing mode and save our file under some name with the extension that matches the file we want to download (if we want to download a photo, the extension must be for example jpg).


Full code:

After the code is executed, the image will appear in the current working directory. With this method we can easily download a single image, but what if we want to download several files at once? Let’s go to the next method to learn it!

Method 2 – Requests Module & Beautifulsoup Class from bs4 Module

If you want to download several files from one page, this method is ideal. At the beginning we import the requests and bs4 modules (from which we take the BeautifulSoup class) and create variables:

  • url – link to the page from which you want to download files,
  • result – link to the page and its html code,
  • soup – BeautifulSoup class object (we use it to find elements),
  • data – the data we are interested in, in this case the html code lines that start with <a> and end with </a> (these code lines have a href attribute which has a link to something).

Then we have to write a function that checks if the links have the mp3 extension and then the same function downloads files with this extension:

Full code:

Using this method, we can download even dozens of files!

Method 3 – urllib Module

The urllib module is provided by default in Python, so you do not need to install it before use.

.align-self-*

First, we import urllib.request, because it contains the urlretrieve() function, which allows us to download images or music files. This function has 4 arguments (1 obligatory and 3 optional), however the first two are most important:

  • url – link to the file you want to get,
  • filename – the name under which you want to save the file.

Note: According to the documentation, urllib.request.urlretrieve is a “legacy interface” and “might become deprecated in the future”

However, there is another way to download the file using this module:

Using this method we also import urllib.request, but we use other functions, first urlopen() to connect to the page, then read() to save the html code of the page in a variable, next we open the file with the name saved in the filename variable and save the html code of the file in binary form. This way we have the file we wanted!

Utility

Method 4 – dload Module

  • In Python version >= 3.6, you can also use the dload module to download a file. The save() function has 3 arguments (1 mandatory, 2 optional):
  • url – link to the file,
  • path – the name under which you want to save your file, if you don’t specify a name, the name will depend on the ending of the link to the file (in our case the file would be called 2cdad67c44b002e7ead0cc35693c0e8b.jpg, so it is better to specify your filename),
  • overwrite – If there is a file with the same name in our working directory, it will overwrite it, if it equals True, and if False, it will not download the file (default = False).

Summary

Sheet

You’ve learned an explanation of how to check if we have permission to download files. You’ve learned that there are 4 methods of downloading files using modules named in order: requests, requests in beautifulsoup, urllib in dload.

Bs4 Cheat Sheet Download

I hope this article will help you to download all the files you want.

Beautiful Soup Documentation - Read The Docs

Related Posts