I have been given the task to scrape a high number of websites. All of them represent (visually speaking) the data I'm interested in in a similar way. Each one of those websites has a product-details-view (so to call it). And all of the views contain the same information: a product title, price, maybe some images, a description, etc...
If I had to scrape 10 sites, I'd write 10 if/else or case in order to handle them, but I'm afraid the number of websites is quite bigger. And thus I'm getting into a whole other problem.
Then I figured out I'd use "computer vision" and "machine learning". That sounds reasonable in the sense of having almost identical websites and "teaching" an algorithm how to "see" the data I'm interested in.
My strategy, so far, is to render each product-detail-view in a headless chrome (controlled with selenium), take a screenshot and split the visual representation of the website into chunks: left column, main, right column. Then split the "main" part into several chunks: title, breadcrumb, content, etc...
Unfortunately I'm not really sure how to actually split the screenshot into chunks. I have been looking at OpenCV's docs, but I'm not sure it's suited for that concrete purpose (or is it?).
Are there any other libraries that would be a better fit for what I'm trying to do? Also, does my strategy sound good or are there better ways of approaching this problem?
PS: Diffbot, Import.io and similar are not an option. Please don't suggest them.
You can try to solve the problem more engineering approach instead of machine learning. I mean to have one code for all the websites, but different configs for each of them. Some example of the config:
title: '#title_id',
description: '#description_id',
price: '#price_id'
Such approach will need some support in the future, because markup can be changed. But can be good to start for now.
Related
First of all I want to apologize if my question is too broad or generic, but it would really save me a lot of needlessly wasted time to get an answer to guide me in the right direction for the work I want to do. With that out of the way, here it goes.
I am trying to retrieve some publicly available data from a website, to create a dataset to work with for a Data Science project. My big issue is that the website does not have a friendly way to download it, and, from what I gathered, it also has no API. So, getting the data requires skills that I do not possess. I would love to learn how to scrape the website (the languages I am most comfortable with are Python and R), and it would add some value to my project if I did it, but I also am somewhat pressured by time constraints, and don't know if it is even possible to scrape the website, much less to learn how to do it in a few days.
The website is this one https://www.rnec.pt/pt_PT/pesquisa-de-estudos-clinicos. It has a search box, and the only option I configure is to click the banner that says "Pesquisa Avançada" and then mark the box that says "Menor de 18 anos". I then click the "Pesquisar" button in the lower-right, and the results that show up are the ones that I want to extract (either that or, if it's simpler, all the results, without checking the "Menor de 18 anos" box). In my computer, 2 results show up per page, and there are 38 pages total. Each result has some of it details in the page where the results appear but, to get the full data from each entry, one has to click "Detalhes" in the lower right of each result, which opens a display with all the data from that result. If possible, I would love to download all the data from that "Detalhes" page of each result (the data there alerady contains the fields that show up in the search result page).
Honestly, I am ready to waste a whole day manually transcribing all the data, but it would be much better to do it computationally, even it it takes me two or three days to learn and do it.
I think that, for someone with experience in web scraping, it is probably super simple to check if it is possible to download the data I described, and what is the best way to go about it (in general terms, I would research and learn it). But I really am lost when it comes to this, and just kindly want to ask for some help in showing me the way go about it (even if the answer is "it is too complicated/impossible, just do it manually"). I know that there are some Python packages for web scraping, like BeautifulSoup and Selenium, but I don't really know if either of them would be appropriate.
I am sorry if my request is not exactly a short and simple coding question, but I have to try to gather any help or guidance I can get. Thank you in advance to everyone who reads my question and a special thank you if you are able to give me some pointers.
So I'm new to python and just finished my first application. (Giving random chords to be played on a midi piano and increasing the score if the right notes are hit in a graphical interface, nothing too fancy but also non-trivial.) And now I'm looking for a new challenge, this time I'm going to try and create a program that monitors a poker table and collects data on all the players. Though this is completely allowed on almost all poker rooms (example of the largest one) there is obviously no set and go API available. This probably makes the extraction of relevant data the most challenging part of the entire program. In my search for more information, I came across an undergraduate thesis that goes in to writing such a program using Java (Internet Poker: Data Collection and Analysis - Haruyoshi Sakai).
In this thesis, the author speaks of 3 data collection methods:
Sniffing packets
Hand history
Scraping the screen
Like the author, I've come to the conclusion that the third option is probably the best route, but unlike him I have no knowledge of how to start this.
What I do know is the following: Any table will look like the image below. Note how text, including numbers is written in the same font on the table. Additionally, all relevant information is also supplied in the chat box situated in the lower left corner of the window.
In some regards using the chat box sounds like the best way to go, seeing as all text is predictable and in the same font. The problem I see is computational speed: It will often occur that many actions get executed in rapid succession. Any program will have to be able to keep up with this.
On the other hand, using the table as reference means that you have to deal with unpredictable bet locations.
The plan: Taking this in to a count, I'd start by getting an index of all player's names and stacks from the table view and "initialising" the table that way, and continue to use their stacks to extrapolate the betting they do.
The Method: Of course, the method is the entire reason why I made this post. It seems to me like one would need some sort of OCR to achieve all this, but seeing as everything is in a known font, there may be some significant optimisations that can be made. I would love some input on resources to learn about solutions to similar problems. Or if you've got a better idea on how to tackle this problem, I'd love to hear that too!
Please do be sure to ask any questions you may have, I will be happy to answer them in as much detail as possible.
My company has slightly more than 300 vehicle based windows CE 5.0 mobile devices that all share the same software and usage model of Direct Store Delivery during the day then doing a Tcom at the home base every night. There is an unknown event(s) that results in the device freaking out and rebooting itself in the middle of the day. Frequency of this issue is ~10 times per week across the fleet of computers that all reboot daily, 6 days a week. The math is 300*6=1800 boots per week (at least) 10/1800= 0.5%. I realize that number is very low, but it is more than my boss wants to have.
My challenge, is to find a way to scan through several thousand logfille.txt files and try to find some sort of pattern. I KNOW there is a pattern here somewhere. I’ve got a couple ideas of where to start, but I wanted to throw this out to the community and see what suggestions you all might have.
A bit of background on this issue. The application starts a new log file at each boot. In an orderly (control) log file, you see the app startup, do its thing all day, and then start a shutdown process in a somewhat orderly fashion 8-10 hours later. In a problem log file, you see the device startup and then the log ends without any shutdown sequence at all in a time less than 8 hours. It then starts a new log file which shares the same date as the logfile1.old that it made in the rename process. The application that we have was home grown by windows developers that are no longer with the company. Even better, they don’t currently know who has the source at the moment.
I’m aware of the various CE tools that can be used to detect memory leaks (DevHealth, retail messages, etc..) and we are investigating that route as well, however I’m convinced that there is a pattern to be found, that I’m just not smart enough to find. There has to be a way to do this using Perl or Python that I’m just not seeing. Here are two ideas I have.
Idea 1 – Look for trends in word usage.
Create an array of every unique word used in the entire log file and output a count of each word. Once I had a count of the words that were being used, I could run some stats on them and look for the non-normal events. Perhaps the word “purple” is being used 500 times in a 1000 line log file ( there might be some math there?) on a control and only 4 times on a 500 line problem log? Perhaps there is a unique word that is only seen in the problem files. Maybe I could get a reverse “word cloud”?
Idea 2 – categorize lines into entry-type and then look for trends in the sequence of type of entry type?
The logfiles already have a predictable schema that looks like this = Level|date|time|system|source|message
I’m 99% sure there is a visible pattern here that I just can’t find. All of the logs got turned up to “super duper verbose” so there is a boatload of fluff (25 logs p/sec , 40k lines per file) that makes this even more challenging. If there isn’t a unique word, then this has almost got to be true. How do I do this?
Item 3 – Hire a windows CE platform developer
Yes, we are going down that path as well, but I KNOW there is a pattern I’m missing. They will use the tools that I don’t have) or make the tools that we need to figure out what’s up. I suspect that there might be a memory leak, radio event or other event that platform tools I’m sure will show.
Item 4 – Something I’m not even thinking of that you have used.
There have got to be tools out there that do this that aren’t as prestigious as a well-executed python script, and I’m willing to go down that path, I just don’t know what those tools are.
Oh yeah, I can’t post log files to the web, so don’t ask. The users are promising to report trends when they see them, but I’m not exactly hopeful on that front. All I need to find is either a pattern in the logs, or steps to duplicate
So there you have it. What tools or techniques can I use to even start on this?
was wondering if you'd looked at the ELK stack? It's an acronym for elasticsearch, kibana and log stash and fits your use case closely; it's often used for analysis of large numbers of log files.
Elasticsearch and kibana gives you a UI that lets you interactively explore and chart data for trends. Very powerful and quite straight forward to set up on a Linux platform and there's a Windows version too. (Took me a day or two of setup but you get a lot of functional power from it). Software is free to download and use. You could use this in a style similar to idea 1 / 2
https://www.elastic.co/webinars/introduction-elk-stack
http://logz.io/learn/complete-guide-elk-stack/
On the question of Python / idea 4 (which elk could be considered part of) I haven't done this for log files but I have used Regex to search and extract text patterns from documents using Python. That may also help you find patterns if you had some leads on the sorts of patterns you are looking for.
Just a couple of thoughts; hope they help.
There is no input data at all to this problem so this answer will be basically pure theory, a little collection of ideas you could consider.
To analize patterns out of a bunch of many logs you could definitely creating some graphs displaying relevant data which could help to narrow the problem, python is really very good for these kind of tasks.
You could also transform/insert the logs into databases, that way you'd be able to query the relevant suspicious events much faster and even compare massively all your logs.
A simpler approach could be just focusing on a simple log showing the crash, instead wasting a lot of efforts or resources trying to find some kind of generic pattern, start by reading through one simple log in order to catch suspicious "events" which could produce the crash.
My favourite approach for these type of tricky problems is different from the previous ones, instead of focusing on analizing or even parsing the logs I'd just try to reproduce the bug/s in a deterministic way locally (you don't even need to have the source code). Sometimes it's really difficult to replicate the production environment in your the dev environment but definitely is time well invested. All the effort you put into this process will help you to solve not only these bugs but improving your software much faster. Remember, the more times you're able to iterate the better.
Another approach could just be coding a little script which would allow you to replay logs which crashed, not sure if that'll be easy in your environment though. Usually this strategy works quite well with production software using web-services where there will be a lot of tuples with data-requests and data-retrieves.
In any case, without seeing the type of data from your logs I can't be more specific nor giving much more concrete details.
I would like to scrape several different discussions forums, most of which have different HTML formats. Rather than dissecting the HTML for each page, it would be more efficient (and fun) to implement some sort of Learning Algorithm that could identify the different messages (i.e. structures) on each page, and individually parse them while simultaneously ignoring all the extraneous crap (i.e., ads and other nonsense). Could someone please point me to some references or sample code for work that's already been carried out in this area.
Moreover, does anyone know of pseudocode for Arc90's readability code?
http://www.minvolai.com/blog/decruft-arc90s-readability-in-python/
build a solution that:
takes some sample webpages with the same structure (eg forum threads)
analyzes the DOM tree of each to find which parts are the same / different
where they are different is the dynamic content you are after (posts, user names, etc)
This technique is known as wrapper induction.
There seems to be a Python port of arc90's Readability script that might point you in the right direction (or at least some direction).
Maybe not exactly correct but there's an O'Reilly book called 'Collective Intelligence' that may lead you in the right direction for what you are attempting to do. Additionally, many of the examples are in python :)
Overall Plan
Get my class information to automatically optimize and select my uni class timetable
Overall Algorithm
Logon to the website using its
Enterprise Sign On Engine login
Find my current semester and its
related subjects (pre setup)
Navigate to the right page and get the data from each related
subject (lecture, practical and
workshop times)
Strip the data of useless
information
Rank the classes which are closer
to each other higher, the ones on
random days lower
Solve a best time table solution
Output me a detailed list of the
BEST CASE information
Output me a detailed list of the
possible class information (some
might be full for example)
Get the program to select the best
classes automatically
Keep checking to see if we can
achieve 7.
6 in detail
Get all the classes, using the lectures as a focus point, would be highest ranked (only one per subject), and try to arrange the classes around that.
Questions
Can anyone supply me with links to something that might be similar to this hopefully written in python?
In regards to 6.: what data structure would you recommend to store this information in? A linked list where each object of uniclass?
Should i write all information to a text file?
I am thinking uniclass to be setup like the following
attributes:
Subject
Rank
Time
Type
Teacher
I am hardly experienced in Python and thought this would be a good learning project to try to accomplish.
Thanks for any help and links provided to help get me started, open to edits to tag appropriately or what ever is necessary (not sure what this falls under other than programming and python?)
EDIT: can't really get the proper formatting i want for this SO post ><
Depending on how far you plan on taking #6, and how big the dataset is, it may be non-trivial; it certainly smacks of NP-hard global optimisation to me...
Still, if you're talking about tens (rather than hundreds) of nodes, a fairly dumb algorithm should give good enough performance.
So, you have two constraints:
A total ordering on the classes by score;
this is flexible.
Class clashes; this is not flexible.
What I mean by flexible is that you can go to more spaced out classes (with lower scores), but you cannot be in two classes at once. Interestingly, there's likely to be a positive correlation between score and clashes; higher scoring classes are more likely to clash.
My first pass at an algorithm:
selected_classes = []
classes = sorted(classes, key=lambda c: c.score)
for clas in classes:
if not clas.clashes_with(selected_classes):
selected_classes.append(clas)
Working out clashes might be awkward if classes are of uneven lengths, start at strange times and so on. Mapping start and end times into a simplified representation of "blocks" of time (every 15 minutes / 30 minutes or whatever you need) would make it easier to look for overlaps between the start and end of different classes.
BeautifulSoup was mentioned here a few times, e.g get-list-of-xml-attribute-values-in-python.
Beautiful Soup is a Python HTML/XML parser designed for quick turnaround projects like screen-scraping. Three features make it powerful:
Beautiful Soup won't choke if you give it bad markup. It yields a parse tree that makes approximately as much sense as your original document. This is usually good enough to collect the data you need and run away.
Beautiful Soup provides a few simple methods and Pythonic idioms for navigating, searching, and modifying a parse tree: a toolkit for dissecting a document and extracting what you need. You don't have to create a custom parser for each application.
Beautiful Soup automatically converts incoming documents to Unicode and outgoing documents to UTF-8. You don't have to think about encodings, unless the document doesn't specify an encoding and Beautiful Soup can't autodetect one. Then you just have to specify the original encoding.
Beautiful Soup parses anything you give it, and does the tree traversal stuff for you. You can tell it "Find all the links", or "Find all the links of class externalLink", or "Find all the links whose urls match "foo.com", or "Find the table heading that's got bold text, then give me that text."
Valuable data that was once locked up in poorly-designed websites is now within your reach. Projects that would have taken hours take only minutes with Beautiful Soup.
There are waaay too many questions here.
Please break this down into subject areas and ask specific questions on each subject. Please focus on one of these with specific questions. Please define your terms: "best" doesn't mean anything without some specific measurement to optimize.
Here's what I think I see in your list of topics.
Scraping HTML
1 Logon to the website using its Enterprise Sign On Engine login
2 Find my current semester and its related subjects (pre setup)
3 Navigate to the right page and get the data from each related subject (lecture, practical and workshop times)
4 Strip the data of useless information
Some algorithm to "rank" based on "closer to each other" looking for a "best time". Since these terms are undefined, it's nearly impossible to provide any help on this.
5 Rank the classes which are closer to each other higher, the ones on random days lower
6 Solve a best time table solution
Output something.
7 Output me a detailed list of the BEST CASE information
8 Output me a detailed list of the possible class information (some might be full for example)
Optimize something, looking for "best". Another undefinable term.
9 Get the program to select the best classes automatically
10 Keep checking to see if we can achieve 7.
BTW, Python has "lists". Whether or not they're "linked" doesn't really enter into it.