How to convert lowercase to uppercase in php string

How to convert php string from lowercase to uppercase: 1. Use strtoupper() function, syntax "strtoupper($string)"; 2. Use mb_strtoupper() function, syntax "mb_strtoupper($string,$encoding) )".

The operating environment of this tutorial: windows7 system, PHP7.1 version, DELL G3 computer

php string will Convert lowercase to uppercase

Method 1: Use strtoupper() function

strtoupper() function can convert letters in a string to uppercase , the syntax format is as follows:

strtoupper($string)

Among them, $string is a parameter of string type. This function can convert the letters in the parameter $string to uppercase and return the converted string.

The sample code is as follows:

<?php
$str = "https://www.php.cn/";
$str = strtoupper($str);
echo $str;
?>

The running results are as follows:

HTTPS://WWW.PHP.CN/

Method 2: Use the mb_strtoupper() function

mb_strtoupper( ) The function of the function is similar to the strtoupper() function. It can also convert letters in the string to uppercase, and the mb_strtoupper() function can also set the character encoding of the parameter. Its syntax is as follows:

mb_strtoupper($string [, $encoding = mb_internal_encoding()])

Among them, $string is the string that needs to be converted, and $encoding is an optional parameter used to set the character encoding of the parameter.

The difference from the strtoupper() function is that the letters in $string are determined through the Unicode character attribute. Therefore, the mb_strtoupper() function is not affected by the locale setting and can convert any character with a "letter" attribute, such as a umlaut (ä).

The sample code is as follows:

<?php
header("Content-type:text/html;charset=utf-8");
$str = "https://www.php.cn/";
$str = mb_strtoupper($str);
echo $str . &#39;<br>&#39;;
$str = "Τάχιστη αλώπηξ βαφής ψημένη γη, δρασκελίζει υπέρ νωθρού κυνός";
$str = mb_strtoupper($str, &#39;UTF-8&#39;);
echo $str;
?>

The running results are as follows:

##Recommended learning:

php training

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