logo
down
shadow

How to control the order of yield in Scrapy


How to control the order of yield in Scrapy

By : John Gatti
Date : November 22 2020, 09:00 AM
With these it helps you need to yield the item on the final callback, parse isn't stopping for parse_member to finish, so the group_item in parse isn't changing while parse_member is working.
Don't yield the group_item of parse, just the one on parse_member, as you already copied the previous item on meta and you already recovered it on parse_member with response.meta['group_item']
code :


Share : facebook icon twitter icon
yield multiple request to a same parse function. what is the order of function running? Scrapy

yield multiple request to a same parse function. what is the order of function running? Scrapy


By : ccharron
Date : March 29 2020, 07:55 AM
will be helpful for those in need You are reusing the same webdriver instance in the second_parse() method. I suspect this is what causing problems since the already instantiated webdriver navigates to a different page when not done with the current. You should instantiate and then close a webdriver in the second_parse() method:
code :
def second_parse(self, response):
   webDriver = webdriver.Firefox()
   webDriver.get(url)

   # scrape

   webDriver.close()
How to yield several requests in order in Scrapy?

How to yield several requests in order in Scrapy?


By : user2077190
Date : March 29 2020, 07:55 AM
Hope that helps Use a return statement instead of yield.
You don't even need to touch any setting:
code :
from scrapy.spiders import Spider, Request

class MySpider(Spider):

    name = 'toscrape.com'
    start_urls = ['http://books.toscrape.com/catalogue/page-1.html']

    urls = (
        'http://books.toscrape.com/catalogue/page-{}.html'.format(i + 1) for i in range(50)
    )

    def parse(self, response):
        for url in self.urls:
            return Request(url)
2018-11-20 03:35:43 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://books.toscrape.com/catalogue/page-1.html> (referer: http://books.toscrape.com/catalogue/page-1.html)
2018-11-20 03:35:43 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://books.toscrape.com/catalogue/page-2.html> (referer: http://books.toscrape.com/catalogue/page-1.html)
2018-11-20 03:35:44 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://books.toscrape.com/catalogue/page-3.html> (referer: http://books.toscrape.com/catalogue/page-2.html)
2018-11-20 03:35:44 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://books.toscrape.com/catalogue/page-4.html> (referer: http://books.toscrape.com/catalogue/page-3.html)
2018-11-20 03:35:45 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://books.toscrape.com/catalogue/page-5.html> (referer: http://books.toscrape.com/catalogue/page-4.html)
2018-11-20 03:35:45 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://books.toscrape.com/catalogue/page-6.html> (referer: http://books.toscrape.com/catalogue/page-5.html)
2018-11-20 03:35:45 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://books.toscrape.com/catalogue/page-7.html> (referer: http://books.toscrape.com/catalogue/page-6.html)
2018-11-20 03:35:46 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://books.toscrape.com/catalogue/page-8.html> (referer: http://books.toscrape.com/catalogue/page-7.html)
2018-11-20 03:35:46 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://books.toscrape.com/catalogue/page-9.html> (referer: http://books.toscrape.com/catalogue/page-8.html)
2018-11-20 03:35:47 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://books.toscrape.com/catalogue/page-10.html> (referer: http://books.toscrape.com/catalogue/page-9.html)
2018-11-20 03:35:47 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://books.toscrape.com/catalogue/page-11.html> (referer: http://books.toscrape.com/catalogue/page-10.html)
2018-11-20 03:35:47 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://books.toscrape.com/catalogue/page-12.html> (referer: http://books.toscrape.com/catalogue/page-11.html)
2018-11-20 03:35:48 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://books.toscrape.com/catalogue/page-13.html> (referer: http://books.toscrape.com/catalogue/page-12.html)
2018-11-20 03:35:48 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://books.toscrape.com/catalogue/page-14.html> (referer: http://books.toscrape.com/catalogue/page-13.html)
2018-11-20 03:35:49 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://books.toscrape.com/catalogue/page-15.html> (referer: http://books.toscrape.com/catalogue/page-14.html)
2018-11-20 03:35:49 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://books.toscrape.com/catalogue/page-16.html> (referer: http://books.toscrape.com/catalogue/page-15.html)
2018-11-20 03:35:50 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://books.toscrape.com/catalogue/page-17.html> (referer: http://books.toscrape.com/catalogue/page-16.html)
2018-11-20 03:35:50 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://books.toscrape.com/catalogue/page-18.html> (referer: http://books.toscrape.com/catalogue/page-17.html)
2018-11-20 03:35:50 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://books.toscrape.com/catalogue/page-19.html> (referer: http://books.toscrape.com/catalogue/page-18.html)
2018-11-20 03:35:51 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://books.toscrape.com/catalogue/page-20.html> (referer: http://books.toscrape.com/catalogue/page-19.html)
2018-11-20 03:35:51 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://books.toscrape.com/catalogue/page-21.html> (referer: http://books.toscrape.com/catalogue/page-20.html)
2018-11-20 03:35:52 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://books.toscrape.com/catalogue/page-22.html> (referer: http://books.toscrape.com/catalogue/page-21.html)
2018-11-20 03:35:52 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://books.toscrape.com/catalogue/page-23.html> (referer: http://books.toscrape.com/catalogue/page-22.html)
2018-11-20 03:35:53 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://books.toscrape.com/catalogue/page-24.html> (referer: http://books.toscrape.com/catalogue/page-23.html)
2018-11-20 03:35:53 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://books.toscrape.com/catalogue/page-25.html> (referer: http://books.toscrape.com/catalogue/page-24.html)
Yield or return for Scrapy?

Yield or return for Scrapy?


By : Fbrufino
Date : March 29 2020, 07:55 AM
wish of those help Yield will return a generator. The return will only return the first v in values and the rest of the loop is skipped. Basically if you use yield, you will get back a generator with all the values in lowercase. If you use a return it will just return the first value in lowercase.
Python Scrapy & Yield

Python Scrapy & Yield


By : James Farr
Date : March 29 2020, 07:55 AM
I wish this helpful for you Normally when obtaining data, you'll have to use Scrapy Items but they can also be replaced with dictionaries (which would be the JSON objects you are referring to), so we'll use them now:
First, start creating the item (or dictionary) in the parse_individual_listings method, just as you did with data in parse_individual_tabs. Then pass it to the next request (that will be caught by parse_individual_tabs with the meta argument, so it should look like:
How to use the `yield Request()` to control the FOR Loop in scrapy?

How to use the `yield Request()` to control the FOR Loop in scrapy?


By : Brushanen
Date : September 29 2020, 07:00 AM
should help you out You could request the next page after parsing the current one. Thus, you could decide to continue if the list is not empty. Eg.
code :
start_urls = ['http://example.com/?p=1']
base_url = 'http://example.com/?p={}'

def parse(self, response):   
    title_list=response.xpath("//div[@class='title']/a/text()").extract()

    # ... do what you want to do with the list, then ...

    if title_list:
        next_page = response.meta.get('page', 1) + 1
        yield Request(
            self.base_url.format(next_page), 
            meta={'page': next_page},  
            callback=self.parse
        )
Related Posts Related Posts :
  • classification of data where attribute values are strings
  • Validate user input using regular expressions
  • Synchronizing and Resampling two timeseries with non-uniform millisecond intraday data
  • determing the number of sentences, words and letters in a text file
  • Deploying impure Python packages to AWS
  • Navigating between multiple Tkinter GUI frames
  • Python - Do I need to remove instances from a dictionary?
  • How can I get the edited values corresponding to the keys of a dictionary in views.py POST method, passed as a context v
  • differentiate between python function and class function
  • From array create tuples on if condition python
  • Looping over a text file list with python
  • Monitoring a real-time data stream with a flask web-app
  • Bad quality after multiple fade effect with pydub
  • delete rows in numpy array in python
  • What are the possible numpy value format strings?
  • Conditional Selecting of child elements in pdfquery
  • Python: split string by closing bracket and write in new line
  • SyntaxWarning: import * only allowed at module level
  • theano ~ use an index matrix and embeddings matrix to produce a 3D tensor?
  • Django background infinite loop process management
  • How can I use Pandas or Numpy to infer a datatype from a list of values?
  • How to add the sum of cubes using a function in python?
  • django registration redux URL's being effected by url with multiple query parameters
  • python - how can I generate a WAV file with beeps?
  • How can I implement a custom RNN (specifically an ESN) in Tensorflow?
  • Python modulo result differs from wolfram alpha?
  • Django on App Engine Managed VM
  • Python - CSV Reading with dictionary
  • Python script works in librarys examples folder, but not in parent directory
  • Dealing with Nested Loops in Python - Options?
  • Get indices of roughly equal sized chunks
  • python - creating dictionary from excel using specific columns
  • SQLAlchemy Determine If Unique Constraint Exists
  • Can I stop rendering variables in Django?
  • Scrapy: traversing a document
  • Common logger settings in Python logging dictConfig
  • Should I pass the object in or build it in the constructor?
  • 3d and 2d subplots in plotly
  • Apache Spark CombineByKey with list of elements in Python
  • How do I round up to the highest multiple of 10 in python?
  • ValueError: invalid literal for int() with base 10: 'skip'
  • How to get entire VARCHAR(MAX) column with Python pypyodbc
  • Use value of variable rather than keyword in python numpy.savez
  • Overlapping cron job that runs the same Django management command: problematic?
  • Distributed Powerset
  • Set a python variable to a C++ object pointer with boost-python
  • How to change array layout?
  • How do I properly structure Templates and include them in the settings in Django 1.8.6?
  • Function parameter semantics (with nested functions)
  • Not enough arguments for format string python
  • How to extract equation from a polynomial fit?
  • How to enable unicode for Python on Fedora?
  • How to check for a POST method in a ListView in Django views? I'm getting a 405 error
  • Pandas fillna values with numpy array
  • How to change the date format in a list of dates
  • Passing a variable between two test cases?
  • h2o: iterate through rows
  • scipy curve_fit fails on easy linear fit?
  • how to multiply dataframes elementwise and create multi-index -- Python
  • Can Django's development server route mutliple sites? If yes, how?
  • shadow
    Privacy Policy - Terms - Contact Us © animezone.co