how to check if php extension is loaded code example

Example: check loaded extensions php

Array
(
    [0] => Core
    [1] => date
    [2] => libxml
    [3] => openssl
    [4] => pcre
    [5] => zlib
    [6] => filter
    [7] => hash
    [8] => Reflection
    [9] => SPL
    [10] => sodium
    [11] => session
    [12] => standard
    [13] => apache2handler
    [14] => mysqlnd
    [15] => PDO
    [16] => xml
    [17] => calendar
    [18] => ctype
    [19] => curl
    [20] => dom
    [21] => mbstring
    [22] => fileinfo
    [23] => ftp
    [24] => gd
    [25] => gettext
    [26] => iconv
    [27] => imagick
    [28] => imap
    [29] => intl
    [30] => json
    [31] => exif
    [32] => mysqli
    [33] => pdo_mysql
    [34] => Phar
    [35] => posix
    [36] => readline
    [37] => shmop
    [38] => SimpleXML
    [39] => soap
    [40] => sockets
    [41] => sysvmsg
    [42] => sysvsem
    [43] => sysvshm
    [44] => tokenizer
    [45] => wddx
    [46] => xmlreader
    [47] => xmlrpc
    [48] => xmlwriter
    [49] => xsl
    [50] => zip
    [51] => Zend OPcache
)