How to convert all php strings to uppercase
Conversion methods: 1. Use strtoupper() function for conversion, syntax "strtoupper(string)"; 2. Use mb_strtoupper() function for conversion, syntax "mb_strtoupper(string, character encoding)" ;3. Use the mb_convert_case() function to convert, the syntax is "mb_convert_case(string, MB_CASE_UPPER, character encoding)".
The operating environment of this tutorial: windows7 system, PHP version 8.1, DELL G3 computer
In PHP, you want to convert a string into Convert all letters to lowercase, you can use the following 3 functions:
Function name | Function |
---|---|
strtoupper | Converts all the characters in the string to uppercase |
mb_strtoupper | Converts all the characters in the string to uppercase (similar to the strtoupper function There are differences) |
mb_convert_case | Convert strings according to different modes |
Method 1: Use strtoupper() function for conversion
strtoupper() function can convert letters in the 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.
<?php header("Content-type:text/html;charset=utf-8"); $str = "https://www.php.cn/"; echo "原字符串:<br> $str <br><br>"; $str = strtoupper($str); echo "转换后:<br> $str"; ?>
Method 2: Use mb_strtoupper() function for conversion
Function of mb_strtoupper() function Similar to the strtoupper() function, the letters in the string can also be converted to uppercase, and the mb_strtoupper() function can also set the character encoding of the parameter. The syntax format is as follows:
mb_strtoupper($str [, $encoding = mb_internal_encoding()])
where, $ str 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 $str 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).
Example 1:
<?php header('content-type:text/html;charset=utf-8'); $str = "hello"; echo "原字符串:<br> $str <br><br>"; $str = mb_strtoupper($str, 'UTF-8'); echo "转换后:<br> $str"; ?>
Example 2:
<?php header("Content-type:text/html;charset=utf-8"); $str = "τάχιστη αλώπηξ βαφήσ ψημένη γη, δρασκελίζει υπέρ νωθρού κυνόσ"; echo "原字符串:<br> $str <br><br>"; $str = mb_strtoupper($str, 'UTF-8'); echo "转换后:<br> $str"; ?>
Method 3: Use the mb_convert_case() function to convert
The mb_convert_case() function can convert strings from upper to lower case. The syntax format is as follows :
mb_convert_case($str, $mode [, $encoding = mb_internal_encoding()])
Among them, $str is the string that needs to be converted; $mode is the conversion mode, which can be MB_CASE_UPPER
(all converted to uppercase), MB_CASE_LOWER
(all One of MB_CASE_TITLE
(convert the first letter to uppercase); $encoding is the character encoding of the parameter and can be omitted.
Compared with the strtolower() and strtoupper() functions, the mb_convert_case() function performs case conversion based on Unicode character attributes. Therefore, the behavior of the mb_convert_case() function is not affected by the locale setting and can convert any character with a "letter" attribute, such as the umlaut A (Ä).
<?php header("Content-type:text/html;charset=utf-8"); $str = 'Hello world!'; echo "原字符串:<br> $str <br><br>"; echo "转换后:<br>"; $str = mb_convert_case($str, MB_CASE_UPPER, "UTF-8"); echo $str.'<br>'; $str = mb_convert_case($str, MB_CASE_LOWER, "UTF-8"); echo $str.'<br>'; $str = mb_convert_case($str, MB_CASE_TITLE, "UTF-8"); echo $str.'<br>'; ?>
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