WordPress doesn’t have an default option to save modified date. So we have save modified date when user updating their profile.
You can save the modified date by adding the following code in your theme’s functions.php file.

/*Save profile modified date*/
function update_profile_modified_date( $user_id ) {
  update_user_meta( $user_id, 'modified_date', date("Y-m-d") );
}
add_action( 'profile_update', 'update_profile_modified_date' );

You can get this date by using get_user_meta() function. for example see below code.

$user_id=25; // replace your user id here
$modified_date = get_user_meta( $user_id, 'modified_date', true ); 

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We have a filter in WordPress for set url to redirect after logout. You can use this filter to redirect back to current page after logout. Add the following code in your theme’s functions.php file..

/* Logout and return to the page they were on*/
function admin_logout_redirect($logouturl, $redir)
    {
        return $logouturl . '&redirect_to=http://'.$_SERVER['HTTP_HOST'].$_SERVER['REQUEST_URI'];
    }
add_filter('logout_url', 'admin_logout_redirect', 10, 2);

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WordPress added the following code in your header for support emoji.

window._wpemojiSettings = {"baseUrl":"http:\/\/s.w.org\/images\/core\/emoji\/72x72\/","ext":".png","source":{"concatemoji":"http:\/\/your-url\/wp-includes\/js\/wp-emoji-release.min.js?ver=4.2.1"}};
    !function(a,b,c){function d(a){var c=b.createElement("canvas"),d=c.getContext&&c.getContext("2d");return d&&d.fillText?(d.textBaseline="top",d.font="600 32px Arial","flag"===a?(d.fillText(String.fromCharCode(55356,56812,55356,56807),0,0),c.toDataURL().length>3e3):(d.fillText(String.fromCharCode(55357,56835),0,0),0!==d.getImageData(16,16,1,1).data[0])):!1}function e(a){var c=b.createElement("script");c.src=a,c.type="text/javascript",b.getElementsByTagName("head")[0].appendChild(c)}var f;c.supports={simple:d("simple"),flag:d("flag")},c.supports.simple&&c.supports.flag||(f=c.source||{},f.concatemoji?e(f.concatemoji):f.wpemoji&&f.twemoji&&(e(f.twemoji),e(f.wpemoji)))}(window,document,window._wpemojiSettings);

img.wp-smiley,
img.emoji {
    display: inline !important;
    border: none !important;
    box-shadow: none !important;
    height: 1em !important;
    width: 1em !important;
    margin: 0 .07em !important;
    vertical-align: -0.1em !important;
    background: none !important;
    padding: 0 !important;
}

you can remove this WordPress emoji code by WordPress actions. Add the following codes in your functions.php file located in your theme folder.

/*Remove WordPress emoji code programmatically without plugin*/
remove_action('wp_head', 'print_emoji_detection_script', 7);
remove_action('wp_print_styles', 'print_emoji_styles');

remove_action( 'admin_print_scripts', 'print_emoji_detection_script' );
remove_action( 'admin_print_styles', 'print_emoji_styles' );

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If you want to get Product id from order id in Woocommerce then fetch order details.

$order = new WC_Order( $order_id );
$items = $order->get_items();

then if you loop through them, you can get all the relevant data:

foreach ( $items as $item ) {
    $product_name = $item['name'];
    $product_id = $item['product_id'];
    $product_variation_id = $item['variation_id'];
}

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If you want to get list of all woocommerce orders by date then using below code. Here change the value of $your_date by yourself.
Assign particular date to $your_date. This code will return the list of woocommerce orders placed in a particular date.

	$your_date = '2016-09-23';
	$args = array(
			'post_type' => 'shop_order',
			'post_status' => 'publish',
			'posts_per_page' => -1,
			'date_query'=> array(
					'after' => $your_date,
					'inclusive' => true,
					)
		);
	$orders = get_posts($args);

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If you want to set blog page programmatically in WordPress then add that following code in your functions.php file. First you have to make sure that blog page is exists or not. if its no exists then create it. After that add that following code in your functions.php file

$blog   = get_page_by_title( 'Blog' );
update_option( 'page_for_posts', $blog->ID );

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If you want to set front page programmatically in WordPress then add that following code in your functions.php file. First you have to make sure that front page is exists or not. if its no exists then create it. After that add that following code in your functions.php file

$home = get_page_by_title( 'Home' );
update_option( 'page_on_front', $home->ID );
update_option( 'show_on_front', 'page' );

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For our customization want to completely disable all types of automatic updates, core or otherwise, add the following to your wp-config.php file

define( 'AUTOMATIC_UPDATER_DISABLED', true );

This code will completely disable all types of automatic updates.

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There is no hooks available to change payment method label in woocommerce checkout page. You can change this label by use your woocommerce checkout settings.

For example
http://www.boopathirajan.com/wp-admin/admin.php?page=wc-settings&tab=checkout

Here replace http://www.boopathirajan.com instead of your web site name.