ucfirst()

(PHP 4, PHP 5, PHP 7)

将字符串的首字母转换为大写

说明

ucfirst(string $str): string

将$str的首字符（如果首字符是字母）转换为大写字母，并返回这个字符串。

注意字母的定义取决于当前区域设定。例如，在默认的“C”区域，字符 umlaut-a（ä）将不会被转换。

参数

$str

输入字符串。

返回值

返回结果字符串。

范例

Example #1ucfirst()范例

<?php
$foo = 'hello world!';
$foo = ucfirst($foo);             // Hello world!
$bar = 'HELLO WORLD!';
$bar = ucfirst($bar);             // HELLO WORLD!
$bar = ucfirst(strtolower($bar)); // Hello world!
?>

参见

• lcfirst() 使一个字符串的第一个字符小写
• strtolower() 将字符串转化为小写
• strtoupper() 将字符串转化为大写
• ucwords() 将字符串中每个单词的首字母转换为大写

Simple multi-bytes ucfirst():
<?php
function my_mb_ucfirst($str) {
  $fc = mb_strtoupper(mb_substr($str, 0, 1));
  return $fc.mb_substr($str, 1);
}
?>

A proper Turkish solution;
<?php
function ucfirst_turkish($str) {
  $tmp = preg_split("//u", $str, 2, PREG_SPLIT_NO_EMPTY);
  return mb_convert_case(
    str_replace("i", "İ", $tmp[0]), MB_CASE_TITLE, "UTF-8").
    $tmp[1];
}
$str = "iyilik güzelLİK";
echo ucfirst($str) ."\n";  // Iyilik güzelLİK
echo ucfirst_turkish($str); // İyilik güzelLİK
?>

I believe that mb_ucfirst will be soon added in PHP, but for now this could be useful
<?php
if (!function_exists('mb_ucfirst') && function_exists('mb_substr')) {
  function mb_ucfirst($string) {
    $string = mb_strtoupper(mb_substr($string, 0, 1)) . mb_substr($string, 1);
    return $string;
  }
}
?>
it also check is mb support enabled or not

This is what I use for converting strings to sentence case:
<?php
function sentence_case($string) {
  $sentences = preg_split('/([.?!]+)/', $string, -1, PREG_SPLIT_NO_EMPTY|PREG_SPLIT_DELIM_CAPTURE);
  $new_string = '';
  foreach ($sentences as $key => $sentence) {
    $new_string .= ($key & 1) == 0?
      ucfirst(strtolower(trim($sentence))) :
      $sentence.' ';
  }
  return trim($new_string);
}
print sentence_case('HMM. WOW! WHAT?');
// Outputs: "Hmm. Wow! What?"
?>

Here's a function to capitalize segments of a name, and put the rest into lower case. You can pass the characters you want to use as delimiters.
i.e. <?php echo nameize("john o'grady-smith"); ?>
returns John O'Grady-Smith
<?php
function nameize($str,$a_char = array("'","-"," ")){  
  //$str contains the complete raw name string
  //$a_char is an array containing the characters we use as separators for capitalization. If you don't pass anything, there are three in there as default.
  $string = strtolower($str);
  foreach ($a_char as $temp){
    $pos = strpos($string,$temp);
    if ($pos){
      //we are in the loop because we found one of the special characters in the array, so lets split it up into chunks and capitalize each one.
      $mend = '';
      $a_split = explode($temp,$string);
      foreach ($a_split as $temp2){
        //capitalize each portion of the string which was separated at a special character
        $mend .= ucfirst($temp2).$temp;
        }
      $string = substr($mend,0,-1);
      }  
    }
  return ucfirst($string);
  }
?>

For lithuanian text with utf-8 encoding I use two functions (thanks [mattalexxpub at gmail dot com] and Svetoslav Marinov)
<?php
function my_ucfirst($string, $e ='utf-8') {
  if (function_exists('mb_strtoupper') && function_exists('mb_substr') && !empty($string)) {
    $string = mb_strtolower($string, $e);
    $upper = mb_strtoupper($string, $e);
      preg_match('#(.)#us', $upper, $matches);
      $string = $matches[1] . mb_substr($string, 1, mb_strlen($string, $e), $e);
  }
  else {
    $string = ucfirst($string);
  }
  return $string;
}
function sentence_case($string) {
  $sentences = preg_split('/([.?!]+)/', $string, -1, PREG_SPLIT_NO_EMPTY|PREG_SPLIT_DELIM_CAPTURE);
  $new_string = '';
  foreach ($sentences as $key => $sentence) {
    $new_string .= ($key & 1) == 0?
      my_ucfirst(strtolower(trim($sentence))) :
      $sentence.' '; 
  }
  return trim($new_string);
}
?>

Improved method of capitalizing first characters of sentences.
The first two manipulations (double spaces & all caps) are optional so can be removed without harm.
<?php
// return string with first letters of sentences capitalized
function ucsentence($str) {
 if ($str) { // input
  $str = preg_replace('/'.chr(32).chr(32).'+/', chr(32), $str); // recursively replaces all double spaces with a space
  if (($x = substr($str, 0, 10)) && ($x == strtoupper($x))) $str = strtolower($str); // sample of first 10 chars is ALLCAPS so convert $str to lowercase; if always done then any proper capitals would be lost
  $na = array('. ', '! ', '? '); // punctuation needles
  foreach ($na as $n) { // each punctuation needle
   if (strpos($str, $n) !== false) { // punctuation needle found
    $sa = explode($n, $str); // split
    foreach ($sa as $s) $ca[] = ucfirst($s); // capitalize
    $str = implode($n, $ca); // replace $str with rebuilt version
    unset($ca); // clear for next loop
   }
  }
  return ucfirst(trim($str)); // capitalize first letter in case no punctuation needles found
 }
}
?>
"heLLo EarthLing!" >> "HeLLo EarthLing!"
"I'M MOSTLY. caps! " >> "I'm mostly. Caps!"
"ALLCAPS" >> "Allcaps"
"i haVe neST.ed punct,u.ation! sp  A c es. and CAPs.. " >> "I haVe neST.ed punct,u.ation! Sp A c es. And CAPs.."

plemieux' function did not work for me without passing the encoding to every single mb function (despite ini_set('default_charset', 'utf-8') at the top of the script). This is the example that works in my application (PHP 4.3):
<?php
function my_mb_ucfirst($str, $e='utf-8') {
  $fc = mb_strtoupper(mb_substr($str, 0, 1, $e), $e); 
  return $fc.mb_substr($str, 1, mb_strlen($str, $e), $e);
}
?>

For some reason this worked for me.
Mac OS 10.5.1 
PHP 5.2.6
<?php
  /**
   * ucfirst UTF-8 aware function
   *
   * @param string $string
   * @return string
   * @see http://ca.php.net/ucfirst
   */
  function my_ucfirst($string, $e ='utf-8') {
    if (function_exists('mb_strtoupper') && function_exists('mb_substr') && !empty($string)) {
      $string = mb_strtolower($string, $e);
      $upper = mb_strtoupper($string, $e);
      preg_match('#(.)#us', $upper, $matches);
      $string = $matches[1] . mb_substr($string, 1, mb_strlen($string, $e), $e);
    } else {
      $string = ucfirst($string);
    }
    return $string;
  }
?>
Svetoslav Marinov
http://slavi.biz

for anyone wanting to ucfirst each word in a sentence this works for me:
<?php
function ucfirst_sentence($str)
{
  return preg_replace('/\b(\w)/e', 'strtoupper("$1")', $str);
}
?>

My version, converst first letter of the first word in the string to uppercase
public function mb_ucfirst($str) {
    $aParts = explode(" ",$str);
    $firstWord = mb_convert_case($aParts[0],MB_CASE_TITLE,"UTF-8");
    unset($aParts[0]);
    return $firstWord." ".implode(" ",$aParts);
  }

Here is the fixed function for Turkish alphabet..
<?php
function uc_first($str){
  $str[0] = strtr($str, 
  "abcdefghijklmnopqrstuvwxyz".
  "\x9C\x9A\xE0\xE1\xE2\xE3".
  "\xE4\xE5\xE6\xE7\xE8\xE9".
  "\xEA\xEB\xEC\xED\xEE\xEF".
  "\xF0\xF1\xF2\xF3\xF4\xF5".
  "\xF6\xF8\xF9\xFA\xFB\xFC".
  "\xFE\xFF", 
  "ABCDEFGHIJKLMNOPQRSTUVWXYZ".
  "\x8C\x8A\xC0\xC1\xC2\xC3\xC4".
  "\xC5\xC6\xC7\xC8\xC9\xCA\xCB".
  "\xCC\xCD\xCE\xCF\xD0\xD1\xD2".
  "\xD3\xD4\xD5\xD6\xD8\xD9\xDA".
  "\xDB\xDC\xDE\x9F");
  return $str;
}
?>

Implementation of multi-bytes ucfirst for "multiword"-strings (module mbstring is required):
<?php
public static function ucfirst($str)
{
  $str = mb_strtolower($str);
  $words = preg_split('/\b/u', $str, -1, PREG_SPLIT_NO_EMPTY);
  foreach ($words as $word) {
    $ucword = mb_strtoupper(mb_substr($word, 0, 1)) . mb_substr($word, 1);
    $str = str_replace($word, $ucword, $str);
  }
  return $str;
}
?>

I made a small change. Now it takes care of points in numbers
function ucsentence ($string){
  $string = explode ('.', $string);
  $count = count ($string);
  for ($i = 0; $i < $count; $i++){
    $string[$i] = ucfirst (trim ($string[$i]));
    if ($i > 0){
      if ((ord($string[$i]{0})<48) || (ord($string[$i]{0})>57)) {
       $string[$i] = ' ' . $string[$i];
      }  
    }
  }
  $string = implode ('.', $string);
  return $string;
}

if you want to ucfirst for utf8 try this one:
<?php
function ucfirst_utf8($stri){
 if($stri{0}>="\xc3")
   return (($stri{1}>="\xa0")?
   ($stri{0}.chr(ord($stri{1})-32)):
   ($stri{0}.$stri{1})).substr($stri,2);
 else return ucfirst($stri);
}
?>
It is quick, not language (but utf8) dependend and does not use any mb-functions such as mb_ucfirst.

Turkish solution:
<?php
mb_internal_encoding("UTF-8");
mb_regex_encoding("UTF-8");
function tr_ilkbuyuk($text)
{
  $text = str_replace("I","ı",$text);
  $text = mb_strtolower($text, 'UTF-8');
  
  if($text[0] == "i")
    $tr_text = "İ".substr($text, 1);
  else
    $tr_text = mb_convert_case($text, MB_CASE_TITLE, "UTF-8");
  
  return trim($tr_text);
}
function tr_ucwords($text)
{
  $p = explode(" ",$text);
  if(is_array($p))
  {
    $tr_text = "";
    foreach($p AS $item)
      $tr_text .= " ".tr_ilkbuyuk($item);
      
    return trim($tr_text);
  }
  else
    return tr_ilkbuyuk($text);
}
$deger = "ıişllşlsdg";
echo tr_ucwords($deger);
?>

Inspired by the lcfirst function a simple mb_lcfirst to cope with multibyte strings:
<?php
function mb_lcfirst($str, $enc = null)
{
 if($enc === null) $enc = mb_internal_encoding();
 return mb_strtolower(mb_substr($str, 0, 1, $enc), $enc).mb_substr($str, 1, mb_strlen($str, $enc), $enc);
}
?>

If someone looks for the equivalent on Oracle DB, here it is: INITCAP. Hope this helps!

In the event you sort of need multiple delimiters to apply the same action to, you can preg_replace this "second delimiter" enveloping it with your actual delimiter.
 
A for instance, would be if you wanted to use something like Lee's FormatName function in an input box designed for their full name as this script was only designed to check the last name as if it were the entire string. The problem is that you still want support for double-barreled names and you still want to be able to support the possibility that if the second part of the double-barreled name starts with "mc", that it will still be formatted correctly.
This example does a preg_replace that surrounds the separator with your actual delimiter. This is just a really quick alternative to writing some bigger fancier blah-blah function. If there's a shorter, simpler way to do it, feel free to inform me. (Emphasis on shorter and simpler because that was the whole point of this.) :D
Here's the example. I've removed Lee's comments as not to confuse them with my own.
<?php
  function FormatName($name=NULL)
  {
    if (empty($name))
      return false;
    $name = strtolower($name);
    $name = preg_replace("[\-]", " - ",$name); // Surround hyphens with our delimiter so our strncmp is accurate
    if (preg_match("/^[a-z]{2,}$/i",$name)) // Simple preg_match if statement
    {
      
      $names_array = explode(' ',$name); // Set the delimiter as a space.
  
      for ($i = 0; $i < count($names_array); $i++)
      {
        if (strncmp($names_array[$i],'mc',2) == 0 || ereg('^[oO]\'[a-zA-Z]',$names_array[$i]))
        {
          $names_array[$i][2] = strtoupper($names_array[$i][2]);
        }
        $names_array[$i] = ucfirst($names_array[$i]);
        
      }
  
      $name = implode(' ',$names_array);
      $name = preg_replace("[ \- ]", "-",$name); // Remove the extra instances of our delimiter
      return ucwords($name);
      
    }
  }
?>

here is how mb_ucfirst should be implemented in userland
<?php
function mb_ucfirst(string $str, string $encoding = null): string
{
  if ($encoding === null) {
    $encoding = mb_internal_encoding();
  }
  return mb_strtoupper(mb_substr($str, 0, 1, $encoding), $encoding) . mb_substr($str, 1, null, $encoding);
}
?>
(when i wrote this comment, everybody else's attempt got it wrong for one reason or another, for example: some don't allow you to specify encoding, and some defaulted to utf-8 instead of defaulting to mb_internal_encoding() )

Simple function for use ucfirst with utf-8 encoded cyrylic text
<?php
  public function capitalize_first($str) {
    $line = iconv("UTF-8", "Windows-1251", $str); // convert to windows-1251
    $line = ucfirst($line);
    $line = iconv("Windows-1251", "UTF-8", $line); // convert back to utf-8
    
    return $line;
  }
?>

@adefoor, Ken and Zee
Changing the case can only be done by understanding the text. Take for example "USA", "Sunday", "March", "I am ...", abbreviations like "prob." and so on.

Ken and zee
One thing I would do to make this more unviersally work would be to add strtolower() around your $sentence. Doing this will allow you to convert an all caps text block as well as an all lowercase text block.
<?php
function sentence_cap($impexp, $sentence_split) {
  $textbad=explode($impexp, $sentence_split);
  $newtext = array();
  foreach ($textbad as $sentence) {
    $sentencegood=ucfirst(strtolower($sentence));
    $newtext[] = $sentencegood;
  }
  $textgood = implode($impexp, $newtext);
  return $textgood;
}
$text = "this is a sentence. this is another sentence! this is the fourth sentence? no, this is the fourth sentence.";
$text = sentence_cap(". ",$text);
$text = sentence_cap("! ",$text);
$text = sentence_cap("? ",$text);
echo $text; // This is a sentence. This is another sentence! This is the fourth sentence? No, this is the fourth sentence.
?>

This is a simple code to get all the 'bad words', stored in a database, out of the text. You could use str_ireplace but since that's installed on PHP5 only, this works as well. It strtolowers the text first then places capitals with ucfirst() where it thinks a capital should be placed, at a new sentence. The previous sentence is ended by '. ' then.
<?php
function filter($text){
  $filters=mysql_query("SELECT word,result FROM filter");
  while($filter=mysql_fetch_array($filters)){
    $text=str_replace($filter[word],$filter[result],strtolower($text));
    $parts=explode(". ",$text);
    for($i=0;$i<count($parts);$i++){
      $parts[$i]=ucfirst($parts[$i]);
    }
    $text=implode(". ",$parts);
  }
  return $text;
}
?>

Ah, the last code were spoiled, here is the fixed one:
<?php
function uc_first($str){
  $str[0] = strtr($str, 
  "abcdefghijklmnopqrstuvwxyz".
  "\x9C\x9A\xE0\xE1\xE2\xE3".
  "\xE4\xE5\xE6\xE7\xE8\xE9".
  "\xEA\xEB\xEC\xED\xEE\xEF".
  "\xF0\xF1\xF2\xF3\xF4\xF5".
  "\xF6\xF8\xF9\xFA\xFB\xFC".
  "\xFD\xFE\xFF", 
  "ABCDEFGHIJKLMNOPQRSTUVWXYZ".
  "\x8C\x8A\xC0\xC1\xC2\xC3\xC4".
  "\xC5\xC6\xC7\xC8\xC9\xCA\xCB".
  "\xCC\xCD\xCE\xCF\xD0\xD1\xD2".
  "\xD3\xD4\xD5\xD6\xD8\xD9\xDA".
  "\xDB\xDC\xDD\xDE\x9F");
  return $str;
}
?>
So, this function changes also other letters into uppercase, ucfirst() does only change: a-z to: A-Z.

Note: the return for this function changed in versions 4.3 when a string is passed of length 0. In <4.2 false is returned and in >4.3 a string of length 0 is returned.
Example:
$name = ucfirst("");
var_dump($name);
$name = ucfirst("owen");
var_dump($name);
Results for <4.2:
bool(false) string(4) "Owen" 
Results for >4.3:
string(0) "" string(4) "Owen"

Here is a handy function that makes the first letter of everything in a sentence upercase. I used it to deal with titles of events posted on my website ... I've added exceptions for uppercase words and lowercase words so roman numeral "IV" doesn't get printed as "iv" and words like "a" and "the" and "of" stay lowercase.
function RemoveShouting($string)
{
 $lower_exceptions = array(
    "to" => "1", "a" => "1", "the" => "1", "of" => "1"
 );
                   
 $higher_exceptions = array(
    "I" => "1", "II" => "1", "III" => "1", "IV" => "1",
    "V" => "1", "VI" => "1", "VII" => "1", "VIII" => "1",
    "XI" => "1", "X" => "1"
 );
 $words = split(" ", $string);
 $newwords = array(); 
 
 foreach ($words as $word)
 {
    if (!$higher_exceptions[$word])
        $word = strtolower($word);
    if (!$lower_exceptions[$word])
        $word = ucfirst($word);
     array_push($newwords, $word);
 
 }
    
 return join(" ", $newwords); 
}

Simple but workable solution:
<?php
mb_internal_encoding("UTF-8"); // before calling the function 
function utf8_ucfirst($str){ 
  preg_match_all("~^(.)(.*)$~u", $str, $arr);
  return mb_strtoupper($arr[1][0]).$arr[2][0];
  }
?>

A combination of the below functions to enable ucfirst for multibyte strings in a shared hosting environment (where you can not always count on mbstring to be installed):
<?php
function my_mb_ucfirst($str, $e='utf-8') {
  if (function_exists('mb_strtoupper')) {
    $fc = mb_strtoupper(mb_substr($str, 0, 1, $e), $e); 
    return $fc.mb_substr($str, 1, mb_strlen($str, $e), $e);
  }
  else { 
    $str = utf8_decode($str);
    $str[0] = strtr($str[0],
      "abcdefghýijklmnopqrstuvwxyz".
      "\x9C\x9A\xE0\xE1\xE2\xE3".
      "\xE4\xE5\xE6\xE7\xE8\xE9".
      "\xEA\xEB\xEC\xED\xEE\xEF".
      "\xF0\xF1\xF2\xF3\xF4\xF5".
      "\xF6\xF8\xF9\xFA\xFB\xFC".
      "\xFE\xFF",
      "ABCDEFGHÝIJKLMNOPQRSTUVWXYZ".
      "\x8C\x8A\xC0\xC1\xC2\xC3\xC4".
      "\xC5\xC6\xC7\xC8\xC9\xCA\xCB".
      "\xCC\xCD\xCE\xCF\xD0\xD1\xD2".
      "\xD3\xD4\xD5\xD6\xD8\xD9\xDA".
      "\xDB\xDC\xDE\x9F");
    return utf8_encode($str);
  }
}
?>

Some simple function for cyrillic and latin letters both:
function rucfirst($str) {
  if(ord(substr($str,0,1))<192) return ucfirst($str);
  else
  return chr(ord(substr($str,0,1))-32).substr($str,1);
}

@ zee: this should solve your !, ?, and any punctuations you want to add. It can probably be cleaned up a bit.
<?php
function sentence_cap($impexp, $sentence_split) {
  $textbad=explode($impexp, $sentence_split);
  $newtext = array();
  foreach ($textbad as $sentence) {
    $sentencegood=ucfirst($sentence);
    $newtext[] = $sentencegood;
  }
  $textgood = implode($impexp, $newtext);
  return $textgood;
}
$text = "this is a sentence. this is another sentence! this is the fourth sentence? no, this is the fourth sentence.";
$text = sentence_cap(". ",$text);
$text = sentence_cap("! ",$text);
$text = sentence_cap("? ",$text);
echo $text; // This is a sentence. This is another sentence! This is the fourth sentence? No, this is the fourth sentence.
?>

Format the input string:
<?php
function ucsentences($string){
  $parts = preg_split('/([^\.\!\?;]+[\.\!\?;"]+)/', strtolower($string), (-1), PREG_SPLIT_DELIM_CAPTURE|PREG_SPLIT_NO_EMPTY); 
  $r = '';
  foreach($parts as $key=>$sentence){
    $r .= ucfirst(trim($sentence)) . ' ';
  }
  $r = preg_replace('/\bi\b/', 'I', $r);
  $r = preg_replace_callback('/("[a-z])/', function($m){ return strtoupper($m[0]);}, $r);
  return rtrim($r);
}
$str = 'i\'m not sure. if this is good enough, but i thought: "hey, who know\'s. maybe i am right."';
?>
Outputs:
I'm not sure. If this is good enough, but I thought: "Hey, who know's. Maybe I am right."

This is what you would expect php to deliver if there was a built-in function named ucsentence.
function ucsentence ($string){
  $string = explode ('.', $string);
  $count = count ($string);
  for ($i = 0; $i < $count; $i++){
    $string[$i] = ucfirst (trim ($string[$i]));
    if ($i > 0){
      $string[$i] = '&nbsp;&nbsp;' . $string[$i];
    }
  }
  $string = implode ('.', $string);
  return $string;
}

In case you need a French version of ucfirst:
"été indien" => "Eté indien"
"ça va?" => "Ça va?"
<?php
function frenchUcfirst($v) {
 $lowCase = "\\xE0\\xE1\\xE2\\xE3\\xE4\\xE5\\xE7\\xE8\\xE9\\xEA\\xEB\\xEC\\xED\\xEE\\xEF";
 $lowCase .= "\\xF1\\xF2\\xF3\\xF4\\xF5\\xF6\\xF8\\xF9\\xFA\\xFB\\xFC\\xFD\\xFF\\u0161";
 $upperCase = "AAAAAA\\xC7EEEEIIIINOOOOOOUUUUYYS";
 return strtoupper(strtr(substr($v, 0, 1), $lowCase, $upperCase)) . substr($v, 1);
}
?>
Note:
- Latin non french accented characters follow the same rule:
"ändå" => "Andå"
- Non ASCII characters in the function are in HEX format to avoid encoding issue...