{"id":592,"date":"2016-06-06T01:53:41","date_gmt":"2016-06-06T07:53:41","guid":{"rendered":"http:\/\/projectopy.com\/programacion\/?p=592"},"modified":"2016-06-06T01:53:41","modified_gmt":"2016-06-06T07:53:41","slug":"php-variables","status":"publish","type":"post","link":"https:\/\/iscodigo.com\/blog\/php\/php-variables\/","title":{"rendered":"PHP: Variables"},"content":{"rendered":"<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_72 counter-hierarchy ez-toc-counter ez-toc-grey ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">Tabla de Contenidos<\/p>\n<span class=\"ez-toc-title-toggle\"><a href=\"#\" class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" aria-label=\"Toggle Table of Content\"><span class=\"ez-toc-js-icon-con\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #999;color:#999\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/span><\/a><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1 eztoc-toggle-hide-by-default' ><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/iscodigo.com\/blog\/php\/php-variables\/#Nombre_de_variable\" title=\"Nombre de variable\">Nombre de variable<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/iscodigo.com\/blog\/php\/php-variables\/#_Referencias\" title=\"\u00a0Referencias\">\u00a0Referencias<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/iscodigo.com\/blog\/php\/php-variables\/#Variable_variables\" title=\"Variable variables\">Variable variables<\/a><\/li><\/ul><\/nav><\/div>\n<h2><span class=\"ez-toc-section\" id=\"Nombre_de_variable\"><\/span>Nombre de variable<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Para nombrar una variable en PHP debe comenzar con el s\u00edmbolo de d\u00f3lar (<code>$<\/code>).<br \/>\nLuego del s\u00edmbolo d\u00f3lar, puede utilizarse letras y el s\u00edmbolo de gui\u00f3n bajo (<code>_<\/code>). Los n\u00fameros no son permitidos ni despu\u00e9s del s\u00edmbolo de d\u00f3lar.<\/p>\n<pre class=\"lang:php decode:true\">&lt;?php\n$_var = 1;   \/\/ V\u00e1lido\n$var = 1;    \/\/ V\u00e1lido\n$1 = 1;      \/\/ Inv\u00e1lido\n$_1hola = 1; \/\/ V\u00e1lido<\/pre>\n<p>Los nombres de variable difieren en\u00a0su capitalizaci\u00f3n<\/p>\n<pre class=\"lang:php decode:true\">&lt;?php\n\n$var = 'Roberto';\n$Var = 'Juan';\necho \"$var, $Var\";      \/\/ imprime \"Roberto, Juan\"<\/pre>\n<h2><span class=\"ez-toc-section\" id=\"_Referencias\"><\/span>\u00a0Referencias<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Por defecto las variables se asignan por valor, lo cual indica que el contenido de una variable se copia hacia otra. Sin embargo, se puede asignar por referencia. Con esto, cuando una variable se referencia o apunta hacia otra, con lo cual si la variable referenciada se cambia lo mismo ocurre con la otra.<\/p>\n<pre class=\"lang:php decode:true\" title=\"Asignaci\u00f3n por Valor\">&lt;?php\n\necho 'Por valor...', PHP_EOL;\n$original = 1;\n$copia = $original;\n\n$original = 100;\n\necho '$original=', $original, PHP_EOL;  \/\/ Valor = 100\necho '$copia=', $copia, PHP_EOL;        \/\/ Valor = 1; No cambia\n<\/pre>\n<pre class=\"lang:php decode:true \" title=\"Asignaci\u00f3n por Referencia\">&lt;?php\necho 'Por referencia...', PHP_EOL;\n$original = 1;\n$copia = &amp; $original;\n\n$original = 100;\n\necho '$original=', $original, PHP_EOL; \/\/ Valor = 100;\necho '$copia=', $copia, PHP_EOL;       \/\/ Valor = 100; Cambi\u00f3<\/pre>\n<h2><span class=\"ez-toc-section\" id=\"Variable_variables\"><\/span>Variable variables<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Son nombres de variables que se pueden definir y usar din\u00e1micamente<\/p>\n<pre class=\"lang:php decode:true  \">&lt;?php\n\n$a = 'hola';\n$hola = 'mundo';\n\n\/\/ Al utilizar $$a, se transforma en $hola\necho $a, ' ', $$a, PHP_EOL;<\/pre>\n","protected":false},"excerpt":{"rendered":"<p>Nombre de variable Para nombrar una variable en PHP debe comenzar con el s\u00edmbolo de d\u00f3lar ($). Luego del s\u00edmbolo d\u00f3lar, puede utilizarse letras y el s\u00edmbolo de gui\u00f3n bajo (_). Los n\u00fameros no son permitidos ni despu\u00e9s del s\u00edmbolo de d\u00f3lar. &lt;?php $_var = 1; \/\/ V\u00e1lido $var = 1; \/\/ V\u00e1lido $1 = [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[46],"tags":[],"class_list":["post-592","post","type-post","status-publish","format-standard","hentry","category-php"],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","jetpack-related-posts":[],"_links":{"self":[{"href":"https:\/\/iscodigo.com\/blog\/wp-json\/wp\/v2\/posts\/592","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/iscodigo.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/iscodigo.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/iscodigo.com\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/iscodigo.com\/blog\/wp-json\/wp\/v2\/comments?post=592"}],"version-history":[{"count":0,"href":"https:\/\/iscodigo.com\/blog\/wp-json\/wp\/v2\/posts\/592\/revisions"}],"wp:attachment":[{"href":"https:\/\/iscodigo.com\/blog\/wp-json\/wp\/v2\/media?parent=592"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/iscodigo.com\/blog\/wp-json\/wp\/v2\/categories?post=592"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/iscodigo.com\/blog\/wp-json\/wp\/v2\/tags?post=592"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}