Recategorizes Posts from data in CSV

page-import.php

<?php
// @Description
// Creates and assigns categories to a list of post URLs via a CSV file

// If we have a file to parse
if ( ($handle = fopen( get_stylesheet_directory() . "/categories.csv", "r" ) ) !== FALSE ) {

	// While we are parsing the CSV
	// Every iteration is 1 row
	// @example fgetcsv($handle, $max_length, $delimiter)
	// @url http://php.net/manual/en/function.fgetcsv.php
	while ( ( $data = fgetcsv( $handle, 2000, "," ) ) !== FALSE ) {

		// Get url from column 1
		$url = $data[0];

		// Change url to ID
		// @url https://codex.wordpress.org/Function_Reference/url_to_postid
		$post_ID = url_to_postid( $url );

		// Put new categories strings in Array from Column2
		// Categories are formated cat1|cat2|cat3|etc...
		$str_cats = preg_split( "/\|/", $data[1] );

		// Create and array to hold our cat IDs
		$new_cats = array();


		// For every item in our array of category strings
		for ( $i = 0, $count = count( $str_cats ); $i < $count; $i++ ) {

			// If the category doesn't already exist
			if ( !is_category( $str_cats[$i] ) ) {
				// Create the new Cat in WP
				// @example wp_create_category( int $cat_ID );
				wp_create_category( $str_cats[$i] );
			}

			// Add category IDs from category string to array using get_cat_ID
			// @example get_cat_ID( str $cat_str );
			// @url https://codex.wordpress.org/Function_Reference/get_cat_ID
			$new_cats[] = get_cat_ID( $str_cats[$i] );
		}

		// Set our Categories
		// @example wp_set_post_categories( int $post_ID, arr $cat_ID, bool $append );
		// @url https://codex.wordpress.org/Function_Reference/wp_set_post_categories
		wp_set_post_categories( $post_ID, $new_cats, FALSE );

	}

	// Close the file so our While loop returns false
	fclose( $handle );
} 

?>