This will copy a string such as 'div. Beautiful Soup is a module for extracting information from an HTML page and is much better for this purpose than regular expressions. To install it, you will need to run pip install --user beautifulsoup4 from the command line.
Check out Appendix A for instructions on installing third-party modules. While beautifulsoup4 is the name used for installation, to import Beautiful Soup you run import bs4. For this chapter, the Beautiful Soup examples will parse that is, analyze and identify the parts of an HTML file on the hard drive.
Open a new file editor tab in Mu, enter the following, and save it as example. As you can see, even a simple HTML file involves many different tags and attributes, and matters quickly get confusing with complex websites. The bs4. BeautifulSoup function returns a BeautifulSoup object. Enter the following into the interactive shell while your computer is connected to the internet:.
BeautifulSoup res. This code uses requests. The BeautifulSoup object that it returns is stored in a variable named noStarchSoup.
Enter the following into the interactive shell after making sure the example. BeautifulSoup exampleFile, 'html. The 'html. However, you can use the faster 'lxml' parser if you install the third-party lxml module. Follow the instructions in Appendix A to install this module by running pip install --user lxml. Forgetting to include this second argument will result in a UserWarning: No parser was explicitly specified warning. You can retrieve a web page element from a BeautifulSoup object by calling the select method and passing a string of a CSS selector for the element you are looking for.
Selectors are like regular expressions: they specify a pattern to look for—in this case, in HTML pages instead of general text strings. Table shows examples of the most common CSS selector patterns.
Selector passed to the select method. The element with an id attribute of author. All elements that use a CSS class attribute named notice. The various selector patterns can be combined to make sophisticated matches. For example, soup.
Instead of writing the selector yourself, you can also right-click on the element in your browser and select Inspect Element. Tag values can be passed to the str function to show the HTML tags they represent.
Tag values also have an attrs attribute that shows all the HTML attributes of the tag as a dictionary. Using the example. BeautifulSoup exampleFile. We store this list of Tag objects in the variable elems , and len elems tells us there is one Tag object in the list; there was one match. The text of an element is the content between the opening and closing tags: in this case, 'Al Sweigart'. Enter this into the interactive shell:.
This time, select gives us a list of three matches, which we store in pElems. Using str on pElems[0] , pElems[1] , and pElems[2] shows you each element as a string, and using getText on each element shows you its text. The get method for Tag objects makes it simple to access attribute values from an element.
Using example. BeautifulSoup open 'example. By middle-clicking a search result link or clicking while holding CTRL , I open the first several links in a bunch of new tabs to read later. I search Google often enough that this workflow—opening my browser, searching for a topic, and middle-clicking several links one by one—is tedious. It would be nice if I could simply type a search term on the command line and have my computer automatically open a browser with all the top search results in new tabs.
A program like this can be adapted to many other websites, although the Google and DuckDuckGo often employ measures that make scraping their search results pages difficult. Open a new file editor tab and save it as searchpypi. Before coding anything, you first need to know the URL of the search result page. The requests module can download this page and then you can use Beautiful Soup to find the search result links in the HTML.
TODO: Open a browser tab for each result. The user will specify the search terms using command line arguments when they launch the program. These arguments will be stored as strings in a list in sys. But how do you figure out the right selector for the job? You just need to find the pattern that all the search result links have. Looking through the rest of the HTML source, it looks like the package-snippet class is used only for search result links. Note that if the PyPI website changes its layout, you may need to update this program with a new CSS selector string to pass to soup.
The rest of the program will still be up to date. Add the following to the end of your program:. By default, you open the first five search results in new tabs using the webbrowser module. However, the user may have searched for something that turned up fewer than five results. The soup. The built-in Python function min returns the smallest of the integer or float arguments it is passed.
There is also a built-in max function that returns the largest argument it is passed. You can use min to find out whether there are fewer than five links in the list and store the number of links to open in a variable named numOpen. Then you can run through a for loop by calling range numOpen. On each iteration of the loop, you use webbrowser. Now you can instantly open the first five PyPI search results for, say, boring stuff by running searchpypi boring stuff on the command line!
See Appendix B for how to easily run programs on your operating system. The benefit of tabbed browsing is that you can easily open links in new tabs to peruse later. A program that automatically opens several links at once can be a nice shortcut to do the following:. Blogs and other regularly updating websites usually have a front page with the most recent post as well as a Previous button on the page that takes you to the previous post.
Then that post will also have a Previous button, and so on, creating a trail from the most recent page to the first post on the site. XKCD is a popular geek webcomic with a website that fits this structure see Figure Downloading each comic by hand would take forever, but you can write a script to do this in a couple of minutes. Open a new file editor tab and save it as downloadXkcd. TODO: Download the image. TODO: Save the image to.
You will download the image files to a folder in the current working directory named xkcd. The call os. The remaining code is just comments that outline the rest of your program. Make your code look like the following:. Otherwise, you create a BeautifulSoup object from the text of the downloaded page. When that happens, the program can just print an error message and move on without downloading the image. At this point, the image file of the comic is stored in the res variable.
You need to write this image data to a file on the hard drive. And in fact, you can call os. You can use this as the filename when saving the image to your hard drive. You join this name with the name of your xkcd folder using os. The code in the for loop writes out chunks of the image data at most , bytes each to the file and then you close the file. The image is now saved to your hard drive. Then the while loop begins the entire download process again for this comic. This project is a good example of a program that can automatically follow links in order to scrape large amounts of data from the web.
Downloading pages and following links are the basis of many web crawling programs. I tried different method to deal with the download: This will give the the csv file in one string: print download. Add a comment. Active Oldest Votes. Community Bot 1 1 1 silver badge. Is it necessary to read the entire thing into memory? This seems non-scaleable. The Aelfinn The Aelfinn I had to also import codecs and wrap the r.
Thanks IrvinH. On Python 3. Best answer! Works great with latest version of Python. To support the widest audience, it should work with all currently-deployed versions of Python, not just the latest For downloading, I think most users will want f. Thx for spotting that. DictReader response. Antti Haapala Antti Haapala k 21 21 gold badges silver badges bronze badges.
Ares Ou Ares Ou 7 7 silver badges 15 15 bronze badges. StringIO r. DictReader csvio : data. Michal Skop Michal Skop 1, 13 13 silver badges 21 21 bronze badges. Python3 Supported Code with closing requests. Hassan Anwer Hassan Anwer 1 1 silver badge 12 12 bronze badges. Justin S Justin S 1, 3 3 gold badges 17 17 silver badges 31 31 bronze badges. So guys we have successfully completed this Python Download File Tutorial. I hope, you found it helpful if yes then must share with others.
And if you have any query regarding this tutorial then feel free to comment. And yes for getting python tutorials stay tuned with Simplified Python. Save my name, email, and website in this browser for the next time I comment. Import urllib. Create a variable and pass the url of file to be downloaded. Copy a network object to a local file.
The wb indicates that the file is opened for writing in binary mode.
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