How to convert text to uppercase in PHP

PHP is a widely used server-side scripting language that can be used to create dynamic web pages and web applications. In actual development, we often need to convert some text or strings to uppercase to make it easier to perform string matching, comparison and other operations. This article will introduce how to convert text to uppercase in PHP.

In PHP, we can use the built-in function strtoupper() to convert a string to uppercase. Its syntax is as follows:

strtoupper(string $string): string

Among them, the $string parameter represents the string to be converted to uppercase and lowercase, and the return value is the converted string. Here is a simple example:

$string = "hello, world!";
$upper = strtoupper($string);
echo $upper;

The execution output will be:

HELLO, WORLD!

If we need to convert all the contents in a file to uppercase in PHP, we can use the following code:

$fp = fopen('test.txt', 'r');
$content = fread($fp, filesize('test.txt'));
fclose($fp);
$upper = strtoupper($content);
echo $upper;

First, we use the fopen() function to open a text file, and then use the fread() function to read the file content into the variable $content. Next, we use the strtoupper() function to convert all characters in $content to uppercase. Finally, we use the echo statement to output the converted content.

In addition to the strtoupper() function, PHP also provides the strtolower() function to convert a string to lowercase, and the ucfirst() function to convert the first character of a string to uppercase. These functions provide a convenient and fast way to convert strings to upper and lower case.

In summary, PHP provides a variety of functions for case conversion. Among them, the strtoupper() function can convert a string to all uppercase letters and is one of our most commonly used functions. When we need to convert a large section of text to uppercase, we can read the file content and use the strtoupper() function to convert the entire file content to uppercase.

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