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

Question

I have texts in UTF-8 with diacritic characters also, and would like to check if first letter of this text is upper case or lower case. How to do this?

Answer 1

If you want it in a nice function, I've used this:

function _is_upper ($in_string)
{
    return($in_string === strtoupper($in_string) ? true : false);
}

Then just call..

if (_is_upper($mystring))
{
  // Do....
}

Answer 2

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

/** Please check below lines. I have elaborate above code. **/

~      ; start 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 match

Answer 3

I think 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';

/** Please check the below lines. I have elaborated above code. **/


~      ; start 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 match

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

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

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

This one is best. Just try it.

Answer 4

Use ctype_upper for check upper case:

$a = array("Word", "word", "wOrd");

foreach($a as $w)
{
    if(ctype_upper($w{0}))
    {
        print $w;
    }
}

Answer 5

Tried ?

$str = 'the text to test';
if($str{0} === strtoupper($str{0})) {
   echo 'yepp, its uppercase';
}
else{
   echo 'nope, its not upper case';
}

Answer 6

I didn't want numbers and others to be an upper char, so I use:

if(preg_match('/[A-Z]$/',$char)==true)
{
   // this must be an upper char
   echo $char
}