isset() \u8207 empty() \u8207 is_null \u9019\u7bc7\u4e3b\u8981\u662f\u6bd4\u8f03\u9019\u4e09\u500b\u5224\u65b7\u51fd\u5f0f\u4ed6\u5011\u4e4b\u9593\u7684\u5dee\u7570\u6027\uff1b\u8acb\u770b\u4ee5\u4e0b\u7a0b\u5f0f\u7bc4\u4f8b\u3002<\/p>\n\n\n
$check=array(true,null,12345,'12345abc','');\necho ' array(true,null,12345,\\'12345abc\\',\\'\\') <br>';\nforeach($check as $value){\n\techo '( '.gettype($value).' ) '.$value.' isset ? : '.(isset($value) ?'TRUE':'FALSE').'<br>';\n\techo '( '.gettype($value).' ) '.$value.' empty ? : '.(empty($value) ?'TRUE':'FALSE').'<br>';\n\techo '( '.gettype($value).' ) '.$value.' is_null ? : '.(is_null($value)?'TRUE':'FALSE').'<br>';\n}\n\/\/PHP \u6709\u500b\u7279\u6027 \u5728\u4f7f\u7528 is_xxx \u51fd\u5f0f\u6642\uff0c\u82e5\u76f4\u63a5echo \u5224\u65b7\u7d50\u679c true \u7684\u8a71 \u6703\u8f38\u51fa 1 false \u5247\u662f \u7a7a\u5b57\u4e32\n\/\/\u6240\u4ee5\u6211\u5011\u8981\u5728\u5224\u65b7\u5f0f\u5f8c\u9762\u81ea\u884c\u52a0\u4e0a\u4e0d\u540c\u7d50\u679c\u6240\u8981\u56de\u50b3\u7684\u5b57\u4e32 'TRUE':'FALSE'\n\/\/gettype \u51fd\u5f0f\u70ba\u53d6\u5f97\u8b8a\u6578\u578b\u614b\n\/\/isset() \u6aa2\u67e5\u8b8a\u6578\u662f\u5426\u6709\u8a2d\u7f6e\n\/\/empty() \u6aa2\u67e5\u8b8a\u6578\u662f\u5426\u70ba\u7a7a\u503c\n\/\/is_null() \u6aa2\u67e5\u8b8a\u6578\u662f\u5426\u70banull\n\/\/\u986f\u793a\u7d50\u679c\n\/*\narray(true,null,12345,'12345abc','')\n( boolean ) 1 isset ? : TRUE\n( boolean ) 1 empty ? : FALSE\n( boolean ) 1 is_null ? : FALSE\n( NULL ) isset ? : FALSE\n( NULL ) empty ? : TRUE\n( NULL ) is_null ? : TRUE\n( integer ) 12345 isset ? : TRUE\n( integer ) 12345 empty ? : FALSE\n( integer ) 12345 is_null ? : FALSE\n( string ) 12345abc isset ? : TRUE\n( string ) 12345abc empty ? : FALSE\n( string ) 12345abc is_null ? : FALSE\n( string ) isset ? : TRUE\n( string ) empty ? : TRUE\n( string ) is_null ? : FALSE\n*\/<\/pre>\n\n\n<\/p>\n","protected":false},"excerpt":{"rendered":"
isset() \u8207 empty() \u8207 is_null \u9019\u7bc7\u4e3b\u8981\u662f\u6bd4\u8f03\u9019\u4e09\u500b\u5224\u65b7\u51fd\u5f0f\u4ed6\u5011\u4e4b\u9593\u7684\u5dee\u7570\u6027\uff1b\u8acb\u770b\u4ee5\u4e0b\u7a0b\u5f0f\u7bc4\u4f8b\u3002<\/p>\n","protected":false},"author":1,"featured_media":2201,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[36],"tags":[237,336,338,422,448,1071,1178],"class_list":["post-3977","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-php","tag-empty","tag-is_null","tag-isset","tag-null","tag-php","tag-1071","tag-1178","hvn-theme-has-thumbnail"],"_links":{"self":[{"href":"https:\/\/www.webteach.tw\/index.php?rest_route=\/wp\/v2\/posts\/3977","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.webteach.tw\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.webteach.tw\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.webteach.tw\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.webteach.tw\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=3977"}],"version-history":[{"count":0,"href":"https:\/\/www.webteach.tw\/index.php?rest_route=\/wp\/v2\/posts\/3977\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.webteach.tw\/index.php?rest_route=\/wp\/v2\/media\/2201"}],"wp:attachment":[{"href":"https:\/\/www.webteach.tw\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=3977"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.webteach.tw\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=3977"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.webteach.tw\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=3977"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}