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Web Scraping Troubleshooting | Missing items when creating a list

Wednesday, April 5, 2017 4:24 AM

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Why do some list items get left out?

Octoparse detects for items belonging to a list via their coding pattern in the underlying HTML source code.

When building a list, we usually start with selecting any 2 items from the list to define a coding pattern for Octoparse to refer to. In this case, if some list items are not included as we expect, then most probably they actually have a coding pattern different from the defined one. 

 

How to tell Octoparse I need those items as well?

To have the omitted items being included, we need to replace the old pattern with a new one. In Octoparse, this refers to modifying or rewriting the XPath expression auto-generated in its previous detection.

If you are new to XPath, you might need to grab some basics of HTML and XPath first. Here are some tutorials for your reference: HTML basic | XPath basic  

 

Where to input the new XPath expression?

Step 1. Select the Loop Item step from the workflow

Step 2. Check the Loop mode option

  • If Variable list mode is on, go to Step 3
  • If Fixed list mode is on, switch to Variable list mode

list_missing_data1

Step 3. Input the modified XPath expression into the textbox

 list_missing_data2

 

Artículo en español:  ¿Cómo lidiar con los elementos faltantes al crear una lista?

También puede leer artículos de web scraping en el sitio web oficial

 

Author: The Octoparse Team

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