Check If a String Is All Caps in PHP

Check if a String is ALL CAPS in PHP

Check whether strtoupper($str) == $str

To handle non-ascii use:

mb_strtoupper($str, 'utf-8') == $str

How to check if letter is upper or lower in PHP?

It is my opinion that making a preg_ call is the most direct, concise, and reliable call versus the other posted solutions here.

echo preg_match('~^\p{Lu}~u', $string) ? 'upper' : 'lower';

My pattern breakdown:

~      # starting pattern delimiter 
^      #match from the start of the input string
\p{Lu} #match exactly one uppercase letter (unicode safe)
~      #ending pattern delimiter 
u      #enable unicode matching

Please take notice when ctype_ and < 'a' fail with this battery of tests.

Code: (Demo)

$tests = ['âa', 'Bbbbb', 'Éé', 'iou', 'Δδ'];

foreach ($tests as $test) {
    echo "\n{$test}:";
    echo "\n\tPREG:  " , preg_match('~^\p{Lu}~u', $test)      ? 'upper' : 'lower';
    echo "\n\tCTYPE: " , ctype_upper(mb_substr($test, 0, 1))  ? 'upper' : 'lower';
    echo "\n\t< a:   " , mb_substr($test, 0, 1) < 'a'         ? 'upper' : 'lower';

    $chr = mb_substr ($test, 0, 1, "UTF-8");
    echo "\n\tMB:    " , mb_strtoupper($chr, "UTF-8") == $chr ? 'upper' : 'lower';
}

Output:

âa:
    PREG:  lower
    CTYPE: lower
    < a:   lower
    MB:    lower
Bbbbb:
    PREG:  upper
    CTYPE: upper
    < a:   upper
    MB:    upper
Éé:               <-- trouble
    PREG:  upper
    CTYPE: lower  <-- uh oh
    < a:   lower  <-- uh oh
    MB:    upper
iou:
    PREG:  lower
    CTYPE: lower
    < a:   lower
    MB:    lower
Δδ:               <-- extended beyond question scope
    PREG:  upper  <-- still holding up
    CTYPE: lower
    < a:   lower
    MB:    upper  <-- still holding up

If anyone needs to differentiate between uppercase letters, lowercase letters, and non-letters see this post.

---

It may be extending the scope of this question too far, but if your input characters are especially squirrelly (they might not exist in a category that Lu can handle), you may want to check if the first character has case variants:

\p{L&} or \p{Cased_Letter}: a letter that exists in lowercase and uppercase variants (combination of Ll, Lu and Lt).

• Source: https://www.regular-expressions.info/unicode.html

To include Roman Numerals ("Number Letters") with SMALL variants, you can add that extra range to the pattern if necessary.

https://www.fileformat.info/info/unicode/category/Nl/list.htm

Code: (Demo)

echo preg_match('~^[\p{Lu}\x{2160}-\x{216F}]~u', $test) ? 'upper' : 'not upper';

How to detect if string contains 1 uppercase letter in PHP

Some regular expression should be able to the work, you can use preg_match and [A-Z]

if(preg_match('/[A-Z]/', $domain)){
 // There is at least one upper
}

How to Check If a String Contains a Specific Word with uppercase and lowercase in PHP

try converting both to the same case:

strpos(strtoupper($company_name), 'SDN');

You could also use preg_match

preg_match('/SDN/i', $company_name);

https://www.php.net/manual/en/function.preg-match.php

PHP uppercase letter in String

You can try this:

if (strtolower($string) != $string) {
    echo 'You have uppercase in your string';
} else {
    echo 'You have no uppercase in your string';
}

This checks if the converted string to lowercase is equal to the original string. Hope this helps...

Identify and get capitalized words in a string in php

You can use a regular expression for it:

preg_match_all('/\b([A-Z]+)\b/', $str, $matches);

To match the lowercase words, use this:

preg_match_all('/\b([a-z]+)\b/', $str, $matches2);

Then you can use functions such as implode() to build the strings.

How to check if input value begins with an uppercase/ or if it has lowercases/ or if it's all uppercase in PHP?

1. To check the first letter with upper case try below

   preg_match("/^[A-Z]/", 'Bamboozler');// This will return true if first letter is upper case
   

2. To check all the character of a string lowercase, you can use ctype_lower() function

   ctype_lower('bamboozler');// This will return true if all the character are lower cases.
   

3. To check all the character of a string uppercase, you can use ctype_upper() function

   ctype_upper('BOOM');// This will return true if all the character is upper cases.
   

PHP: How to convert a string that contains upper case characters

You can use preg_replace to replace any instance of a lowercase letter followed with an uppercase with your lower-dash-lower variant:

$dashedName = preg_replace('/([^A-Z-])([A-Z])/', '$1-$2', $className);

Then followed by a strtolower() to take care of any remaining uppercase letters:

return strtolower($dashedName);

The full function here:

function camel2dashed($className) {
  return strtolower(preg_replace('/([^A-Z-])([A-Z])/', '$1-$2', $className));
}

---

To explain the regular expression used:

/        Opening delimiter
(        Start Capture Group 1
  [^A-Z-]   Character Class: Any character NOT an uppercase letter and not a dash
)        End Capture Group 1
(        Start Capture Group 2
  [A-Z]    Character Class: Any uppercase letter
)        End Capture Group 2
/        Closing delimiter

As for the replacement string

$1  Insert Capture Group 1
-   Literal: dash
$2  Insert Capture Group 2

---

Related Topics