Question

in_category( int|string|array $category,  int|object $post = null )

Check if the current post is within any of the given categories.

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description

The given categories are checked against the post’s categories’ term_ids, names and slugs. Categories given as integers will only be checked against the post’s categories’ term_ids.

Prior to v2.5 of WordPress, category names were not supported. Prior to v2.7, category slugs were not supported. Prior to v2.7, only one category could be compared: in_category( $single_category ). Prior to v2.7, this function could only be used in the WordPress Loop. As of 2.7, the function can be used anywhere if it is provided a post ID or post object.

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参数

$category

(int|string|array) (Required) Category ID, name or slug, or array of said.

$post

(int|object) (Optional) Post to check instead of the current post. (since 2.7.0)

Default value: null

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返回值

(bool) True if the current post is in any of the given categories.

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源代码

File: wp-includes/category-template.php

function in_category( $category, $post = null ) {
	if ( empty( $category ) )
		return false;

	return has_category( $category, $post );
}

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更新日志

Version	description
1.2.0	Introduced.

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相关函数

Uses

• wp-includes/category-template.php: has_category()

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User Contributed Notes

1. Skip to note content You must log in to vote on the helpfulness of this noteVote results for this note: 1You must log in to vote on the helpfulness of this note Contributed by Codex

   Testing the current post outside the Loop
   During a request for an individual post (usually handled by the single.php template), you can test that post’s categories even before the Loop is begun.

   You could use this to switch templates like so:

   
   if ( in_category('fruit') ) {
   	include 'single-fruit.php';
   } elseif ( in_category('vegetables') ) {
   	include 'single-vegetables.php';
   } else {
   	// Continue with normal Loop
   	if ( have_posts() ) : while ( have_posts() ) : the_post();
   	// ...
   }
   

   (The Custom Post Templates Plugin allows for creation of templates for single posts. It also shows an example of how to add a template which is used for all posts in a given category, not just a single post. That example is commented out in the plugin by default but can be easily implemented by uncommenting the appropriate lines.)

Testing the current post within the Loop
in_category() is often used to take different actions within the Loop depending on the current post’s category, e.g.

if ( in_category( 'pachyderms' )) {
	// They have long trunks...
} elseif ( in_category( array( 'Tropical Birds', 'small-mammals' ) )) {
	// They are warm-blooded...
} else {
	// etc.
}