disable the Pay upon Invoice gateway for specific product IDs - WooCommerce PayPal Payments

functions.php

<?php


function remove_ppcp_pui_for_products( $available_gateways ) {

// Not in backend (admin)
if( is_admin() )
return $available_gateways;

// Set var default state
$excluded_pui_product = false;

// Only execute loop on checkout page
if ( is_checkout() ) {
foreach (WC()->cart->get_cart() as $cart_item_key => $cart_item ) {

// Get the WC_Product object
$product = wc_get_product($cart_item['product_id']);
$id = $product->get_id();

// Determine if excluded PUI product is present
if( $id === 16 ) $excluded_pui_product = true;
}

// Remove PayPal Payments gateways for excluded PUI products
if( $excluded_pui_product )
// unset Pay upon Invoice gateway
unset($available_gateways['ppcp-pay-upon-invoice-gateway']); 
}
return $available_gateways;
}
add_filter('woocommerce_available_payment_gateways', 'remove_ppcp_pui_for_products', 10, 1);