ctype_space to validate whitespace character(s) in PHP

Check whitespace with ctype_space()

ctype_space() checks whether every character is whitespace such as a space, tab, newline, carriage return, or form feed.

$value = " 	
";
var_dump(ctype_space($value));

$var=&quot;\t\r\n&quot;; // All are whitespace character(s)
//$var="   "; //  All are whitespace character(s)
//$var=" ab "; // All or some are NOT whitespace character(s)

if(ctype_space($var)){
	echo &quot;&lt;b&gt;$var&lt;/b&gt; All are whitespace character(s)&quot;;
}else{ 
	echo &quot; &lt;b&gt;$var&lt;/b&gt; All or some are NOT whitespace character(s)&quot;;
}

Output

All are whitespace character(s)

Syntax

bool ctype_space ( string $input_string )

$input_string : String to be checked.

ctype_space() is a PHP filter function checks the presence of whitespace character(s) in the $input_string . Any thing other than this if present then it return FALSE.

$str = array('string1' =&gt; "\n\t\r", 'string2' =&gt; "Hello World", 'string3' =&gt; "asd\n\r\t",'string4' =&gt; 45);
foreach ($str as $val =&gt; $string) {
if (ctype_space($string)) {
 echo "<p class='text-success'>The string <b>$val</b> consists of all  whitespace character(s)</p>";
}else {
 echo "<p class='text-danger'>The string <b>$val</b>  consist of non-whitespace character(s)</p>";
 }
}

Output is here

The string string1 consists of all  whitespace character(s)
The string string2  consist of non-whitespace character(s)
The string string3  consist of non-whitespace character(s)
The string string4  consist of non-whitespace character(s)

Example: Validating Whitespace Input

$input = "   ";
if (ctype_space($input)) {
    echo "Input is all whitespace.";
} else {
    echo "Input contains non-whitespace characters.";
}

Output

Input is all whitespace.

Example: Handling Empty Strings

$empty_str = "";
if (ctype_space($empty_str)) {
    echo "Empty string treated as whitespace.";
} else {
    echo "Empty string not treated as whitespace.";
}

Output

Empty string not treated as whitespace.

Example: Comparing ctype_space() and trim()

$input = "  text  ";
echo ctype_space($input) ? "Only whitespace" : "Contains non-whitespace";
echo '<br>';
// This will return false because the string contains "text"
if(trim($input)){
echo trim($input); // text

Explanation:
Whitespace Validation: Demonstrates checking if a string contains only whitespace characters.
Empty Strings: Shows that `ctype_space()` returns false for empty strings.
Difference from `trim(): Highlights the functional difference between removing spaces with `trim()` and checking for spaces with `ctype_space()`.
Check for only alphabetic characters by ctype_alpha() Check for all lower or upper Check for at least one lower case or upper case
ctype()

Subhendu Mohapatra

Author & Instructor at plus2net

I write and maintain practical tutorials on Python, PHP, SQL, JavaScript, HTML, jQuery, and web development at plus2net. The tutorials focus on clear explanations, working examples, and code that readers can test and adapt while learning.

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ctype_space to check all whitespace character(s)

Check whitespace with ctype_space()

Example: Validating Whitespace Input

Example: Handling Empty Strings

Example: Comparing ctype_space() and trim()

Subhendu Mohapatra