- The CallbackFilterIterator class allows you to create…a custom filter using a callback function.…It requires a minimum of PHP 5.4.…If you're using PHP 5.3, the alternative…is to extend the FilterIterator class…which is described later in this chapter.…I've got open callback_filter.php.…It contains the simplexml that was used…earlier in this chapter to extract data…from courses.xml in the common/data directory.…
The only difference is that instead of getting the duration,…this time we're getting the course level.…The first thing we need to do is to convert…the simplexml element into a simplexml iterator.…We do that by adding a second argument…to the simplexml_load_file.…So that's on line two and it's a string SimpleXMLIterator.…Forgetting to convert simplexml elements into iterators…when you want to use them with other iterators…is a common problem, so don't forget to do that.…
So, now we can chain this with the CallbackFilterIterator.…I think I'm going to need quite a lot of space…so I'm going to expand my editing pane.…
Author
Released
10/22/2014- Using SPL iterators
- Inspecting directories
- Working with text files
- Exporting and extracting data
- Filtering data
- Converting between arrays and iterators
- Combining and merging iterators
- Creating a repeat sequence with InfiniteIterator
- Working with data structures
Skill Level Intermediate
Duration
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Introduction
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Welcome59s
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1. Introducing the Standard PHP Library (SPL)
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Introducing SPL iterators1m 59s
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Using SPL iterators2m 6s
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2. Exploring Files and Directories
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3. Filtering Values
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4. Array Iterators
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Filtering values from JSON4m 45s
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5. Combining and Merging Iterators
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6. Other Iterators
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7. SPL Data Structures
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Using SplStack and SplQueue6m 25s
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Understanding heaps2m 55s
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Conclusion
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Goodbye1m 37s
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Video: Creating a custom filter with CallbackFilterIterator