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Get list of post categories in WordPress

<?php 
$categories = get_the_category();
$separator = ' ';
$output = '';
if ( ! empty( $categories ) ) {
	foreach( $categories as $category ) {
		$output .= '<a href="' . esc_url( get_category_link( $category->term_id ) ) . '" alt="' . esc_attr( sprintf( __( 'View all posts in %s', 'textdomain' ), $category->name ) ) . '">' . esc_html( $category->name ) . '</a>' . $separator;
	}
	echo trim( $output, $separator );
}
?>