Convert string to uppercase using PHP function 'strtoupper'

PHP function "strtoupper" is a very useful function that can convert a string to uppercase. In this article, we'll explore how to use this function and provide relevant code examples.

First, let us understand the usage of the "strtoupper" function. This function accepts a string as argument and returns a new string in which all lowercase letters have been converted to uppercase letters. It is worth noting that this function does not affect the original string.

Now, let’s take a look at how to use the "strtoupper" function in PHP.

<?php
    $str = "hello world";

    $upperStr = strtoupper($str);

    echo $upperStr; // 输出 "HELLO WORLD"
?>

In the above code, we define a string variable $str and assign it the value "hello world". We then use the "strtoupper" function to convert this string to uppercase and store the result in the $upperStr variable. Finally, we use the echo statement to output the converted string to the screen.

In addition, the "strtoupper" function can also be used with other PHP string functions to achieve more complex operations. Below is an example that demonstrates how to convert a user-entered string to uppercase and remove spaces.

<?php
    $input = $_POST['input']; // 假设用户输入为 "  hello world  "

    $upperStr = strtoupper(trim($input));

    echo $upperStr; // 输出 "HELLO WORLD"
?>

In the above code, we first get the string from the user's input and store it in the $input variable. Then, we use the trim function to remove spaces from both ends of the string. Finally, we convert the string to uppercase using the strtoupper function and store the result in the $upperStr variable. Finally, we output the converted string to the screen.

To summarize, the PHP function "strtoupper" is a simple and useful function that can convert a string to uppercase. Whether it is for simple conversion operations or combined with other string functions for complex operations, we can flexibly use this function to meet various needs. I hope that through the introduction and sample code of this article, readers can better understand and apply this function.

The above is the detailed content of Convert string to uppercase using PHP function 'strtoupper'. For more information, please follow other related articles on the PHP Chinese website!