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In PHP, the ord() function returns the ASCII value of a character, while the array_map() function can be used to apply a callback function to every element in an array. When we need to process each character of a string in bulk and obtain their ASCII values, these two functions can be combined. This article will explain in detail how to achieve this functionality.
ord() is a built-in PHP function that returns the ASCII value of a character. For example:
<span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-title function_ invoke__">ord</span></span><span>(</span><span><span class="hljs-string">'A'</span></span><span>); </span><span><span class="hljs-comment">// Outputs 65</span></span><span>
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-title function_ invoke__">ord</span></span><span>(</span><span><span class="hljs-string">'a'</span></span><span>); </span><span><span class="hljs-comment">// Outputs 97</span></span><span>
</span></span>This function takes a single character as an argument and returns its ASCII value. For common characters such as uppercase letters, numbers, and lowercase letters, ord() correctly returns their ASCII values.
array_map() is a PHP array function that allows you to apply a callback function to each element of an array, returning a new processed array. For example:
<span><span><span class="hljs-variable">$array</span></span><span> = [</span><span><span class="hljs-number">1</span></span><span>, </span><span><span class="hljs-number">2</span></span><span>, </span><span><span class="hljs-number">3</span></span><span>];
</span><span><span class="hljs-variable">$result</span></span><span> = </span><span><span class="hljs-title function_ invoke__">array_map</span></span><span>(function(</span><span><span class="hljs-variable">$item</span></span><span>) {
</span><span><span class="hljs-keyword">return</span></span><span> </span><span><span class="hljs-variable">$item</span></span><span> * </span><span><span class="hljs-number">2</span></span><span>;
}, </span><span><span class="hljs-variable">$array</span></span><span>);
<p></span>print_r($result); // Outputs [2, 4, 6]<br>
</span>In the above example, array_map() applies the callback function to each element of $array, multiplying each element by 2. The result is a new processed array.
Now, we can combine these two functions to retrieve the ASCII values of every character in a string. First, we convert the string into an array, then use array_map() to apply the ord() function to each character.
<span><span><span class="hljs-meta"><?php</span></span><span>
<p></span>// Original string<br>
$str = "Hello World";</p>
<p>// Convert string to character array<br>
$charArray = str_split($str);</p>
<p>// Use array_map to get ASCII values in bulk<br>
$asciiValues = array_map('ord', $charArray);</p>
<p>// Output the result<br>
print_r($asciiValues);</p>
<p>?><br>
</span>str_split($str): First, split the string $str into an array of characters. For example, "Hello World" becomes ['H', 'e', 'l', 'l', 'o', ' ', 'W', 'o', 'r', 'l', 'd'].
array_map('ord', $charArray): Next, array_map() applies the ord() function to each character, returning the ASCII value of each. For example, the character 'H' becomes 72, the character 'e' becomes 101, and so on.
print_r($asciiValues): Finally, we print the ASCII values array. The result is an integer array representing the ASCII values of each character in the string.
<span><span><span class="hljs-title function_ invoke__">Array</span></span><span>
(
[</span><span><span class="hljs-number">0</span></span><span>] => </span><span><span class="hljs-number">72</span></span><span>
[</span><span><span class="hljs-number">1</span></span><span>] => </span><span><span class="hljs-number">101</span></span><span>
[</span><span><span class="hljs-number">2</span></span><span>] => </span><span><span class="hljs-number">108</span></span><span>
[</span><span><span class="hljs-number">3</span></span><span>] => </span><span><span class="hljs-number">108</span></span><span>
[</span><span><span class="hljs-number">4</span></span><span>] => </span><span><span class="hljs-number">111</span></span><span>
[</span><span><span class="hljs-number">5</span></span><span>] => </span><span><span class="hljs-number">32</span></span><span>
[</span><span><span class="hljs-number">6</span></span><span>] => </span><span><span class="hljs-number">87</span></span><span>
[</span><span><span class="hljs-number">7</span></span><span>] => </span><span><span class="hljs-number">111</span></span><span>
[</span><span><span class="hljs-number">8</span></span><span>] => </span><span><span class="hljs-number">114</span></span><span>
[</span><span><span class="hljs-number">9</span></span><span>] => </span><span><span class="hljs-number">108</span></span><span>
[</span><span><span class="hljs-number">10</span></span><span>] => </span><span><span class="hljs-number">100</span></span><span>
)
</span></span>The result shows that the ASCII value of each character has been successfully extracted.
By combining ord() and array_map(), we can easily retrieve the ASCII values of every character in a string. Using str_split() to split the string into a character array and then applying ord() to each character via array_map(), we can generate a complete array of ASCII values. This approach is both simple and efficient, making it suitable for scenarios where bulk character processing is required.
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