php changes words from lowercase to uppercase

In PHP development, we often encounter the need to convert words in text to uppercase and lowercase. One common scenario is to convert words from lowercase to uppercase. This article will introduce two common methods in PHP to convert words from lowercase to uppercase.

Method 1: strtoupper()

PHP built-in function strtoupper() can convert all lowercase letters in the string to uppercase letters, and it is very simple to use.

The following is an example:

$originalString = "hello world";
$upperString = strtoupper($originalString);
echo $upperString; // 输出 HELLO WORLD

As you can see, we first define an original string $originalString, which contains some lowercase letters. Then, we call the strtoupper() function, passing in the original string as a parameter, and the result is saved in $upperString. Finally, we use echo to output the converted result.

It should be noted that the strtoupper() function can only process English characters, and unpredictable errors may occur for characters in other languages. Therefore, when using the strtoupper() function, be sure to pay attention to whether the string to be converted is an English character.

Method 2: mb_strtoupper()

If the string that needs to be processed contains non-English characters, we can use the PHP built-in function mb_strtoupper() to achieve case conversion operation.

$originalString = "你好，Hello, World!";
$upperString = mb_strtoupper($originalString, 'UTF-8');
echo $upperString; // 输出 你好，HELLO, WORLD!

As you can see, we passed in two parameters to the mb_strtoupper() function. The first parameter is the string that needs to be converted to upper and lower case $originalString, and the second parameter is the character encoding used.

It should be noted that when using the mb_strtoupper() function, the second parameter must be consistent with the character encoding of the string being processed. Otherwise, the conversion results may be incorrect.

Summary

This article introduces two common methods of converting words from lowercase to uppercase, namely strtoupper() and mb_strtoupper() function. Among them, the strtoupper() function is suitable for case conversion of English characters, while the mb_strtoupper() function is suitable for case conversion of non-English characters. In actual development, we have to choose the appropriate method to process according to specific needs.

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