Title: Warning message "Warning: in_array() expects parameter 2 to be array, null given Last modified: August 20, 2016 --- # Warning message "Warning: in_array() expects parameter 2 to be array, null given * [AdreaUI](https://wordpress.org/support/users/adreaui/) * (@adreaui) * [13 years, 8 months ago](https://wordpress.org/support/topic/warning-message-warning-in_array-expects-parameter-2-to-be-array-null-given/) * The site I am working on has many pages with many menus. I currently have the parent pages and their ancestors showing the pertinent menu according to code in the sidebar.php and the following function: * ``` // Check if page is an ancestor function is_ancestor($post_id) { global $wp_query; $ancestors = $wp_query->post->ancestors; if ( in_array($post_id, $ancestors) ) { return true; } else { return false; } } ``` * My news page (where posts are displayed) is a child of About. When I try to call the About Menu as per the rest of the site I get the following warning: * Warning: in_array() expects parameter 2 to be array, null given in /Users/…./ functions.php on line 138 * I am working locally so unfortunately I cannot provide a link to the site. Viewing 8 replies - 1 through 8 (of 8 total) * [s_ha_dum](https://wordpress.org/support/users/apljdi/) * (@apljdi) * [13 years, 8 months ago](https://wordpress.org/support/topic/warning-message-warning-in_array-expects-parameter-2-to-be-array-null-given/#post-3078408) * Check that `$ancestors` is an array before trying to use it: * ``` if ( is_array($ancestors) && in_array($post_id, $ancestors) ) { ``` * Thread Starter [AdreaUI](https://wordpress.org/support/users/adreaui/) * (@adreaui) * [13 years, 8 months ago](https://wordpress.org/support/topic/warning-message-warning-in_array-expects-parameter-2-to-be-array-null-given/#post-3078459) * Sorry for my ignorance. I am learning pHp as I go. * Where should I put this statement? In functions.php or within the sidebar.php where I am trying to call the menu? How would I specifically check the news page? The above function works perfectly for the rest of the site. It is only the posts page (news) that I get the warning on. * [Andrew Nevins](https://wordpress.org/support/users/anevins/) * (@anevins) * WCLDN 2018 Contributor | Volunteer support * [13 years, 8 months ago](https://wordpress.org/support/topic/warning-message-warning-in_array-expects-parameter-2-to-be-array-null-given/#post-3078461) * You prepend your current `if` condition to consider checking for an array, E. g your code should be * ``` // Check if page is an ancestor function is_ancestor($post_id) { global $wp_query; $ancestors = $wp_query->post->ancestors; if ( is_array($ancestors) && in_array($post_id, $ancestors) ) { return true; } else { return false; } } ``` * [s_ha_dum](https://wordpress.org/support/users/apljdi/) * (@apljdi) * [13 years, 8 months ago](https://wordpress.org/support/topic/warning-message-warning-in_array-expects-parameter-2-to-be-array-null-given/#post-3078467) * Yes, what I gave you was a rewrite of one of the lines of code that you provided. * Thread Starter [AdreaUI](https://wordpress.org/support/users/adreaui/) * (@adreaui) * [13 years, 8 months ago](https://wordpress.org/support/topic/warning-message-warning-in_array-expects-parameter-2-to-be-array-null-given/#post-3078474) * Okay gotcha. I amended the code and the warning disappeared. Great! * Now knowing this what would be the recommended way to call the About Menu? This page is still, for all intents and purposes, a child page of About. I still need to call the About Menu but have to do it differently than the current mechanism used for all other pages. * [s_ha_dum](https://wordpress.org/support/users/apljdi/) * (@apljdi) * [13 years, 8 months ago](https://wordpress.org/support/topic/warning-message-warning-in_array-expects-parameter-2-to-be-array-null-given/#post-3078476) * How did you make your blog index a ‘child’ of your about page? * Thread Starter [AdreaUI](https://wordpress.org/support/users/adreaui/) * (@adreaui) * [13 years, 8 months ago](https://wordpress.org/support/topic/warning-message-warning-in_array-expects-parameter-2-to-be-array-null-given/#post-3078477) * I say it’s a child page because it is not a link on the main nav but rather you have to first go to About. Then there is a sub-nav with a News link. * I have the respective menus showing on the rest of the site by using the following code: * ``` 'solutions-menu' )); } elseif ( is_page( 'webcasts' ) || is_ancestor( '17' ) ) { wp_nav_menu(array('menu'=>'webcasts-menu' )); } ?> ``` * This doesn’t seem to be working with the posts page. I also tried naming it directly e.g. * ``` 'solutions-menu' )); } elseif ( is_page( 'news' )) { wp_nav_menu(array('menu'=>'about-menu' )); } ?> ``` * This also doesn’t seem to work. I am getting a menu but not the correct one. Instead I am getting a menu consisting of News and Press Releases. Press Releases is the other post page I have on this site. I use categories to post each to it’s own page. * [s_ha_dum](https://wordpress.org/support/users/apljdi/) * (@apljdi) * [13 years, 8 months ago](https://wordpress.org/support/topic/warning-message-warning-in_array-expects-parameter-2-to-be-array-null-given/#post-3078478) * Ok. You are talking about how you have your links setup, about how your front end user interface is constructed. I need to know how the pages and posts are setup in the backend. I need to know how it looks to the software and how it looks to the server, not how you lead users to it. Viewing 8 replies - 1 through 8 (of 8 total) The topic ‘Warning message "Warning: in_array() expects parameter 2 to be array, null given’ is closed to new replies. ## Tags * [Ancestor](https://wordpress.org/support/topic-tag/ancestor/) * [posts](https://wordpress.org/support/topic-tag/posts/) * [warning](https://wordpress.org/support/topic-tag/warning/) * 8 replies * 3 participants * Last reply from: [s_ha_dum](https://wordpress.org/support/users/apljdi/) * Last activity: [13 years, 8 months ago](https://wordpress.org/support/topic/warning-message-warning-in_array-expects-parameter-2-to-be-array-null-given/#post-3078478) * Status: not resolved ## Topics ### Topics with no replies ### Non-support topics ### Resolved topics ### Unresolved topics ### All topics