Variable handling 函数
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strval

(PHP 4, PHP 5)

strval — 获取变量的字符串值

描述

string strval ( mixed $var )

返回 var 的 string 值。 参见 string 文档获取更多关于字符串转换的信息。

var 可以是任何标量类型。不能将 strval() 用于数组或对象。

参见 floatval()、intval()、settype() 和类型戏法。

Variable handling 函数
在线手册：中文 英文
PHP手册
PHP手册 - N: 获取变量的字符串值

用户评论:

Hayley Watson (22-Aug-2007 04:53)

As of PHP 5.2, strval() will return the string value of an object, calling its __toString() method to determine what that value is.

NyctoFixer at gmail dot com (11-Jun-2007 08:19)

As of PHP 5.1.4 (I have not tested it in later versions), the strval function does not attempt to invoke the __toString method when it encounters an object. This simple wrapper function will handle this circumstance for you:

<?

/**
 * Returns the string value of a variable
 *
 * This differs from strval in that it invokes __toString if an object is given
 * and the object has that method
 */
function stringVal ($value)
{
    // We use get_class_methods instead of method_exists to ensure that __toString is a public method
    if (is_object($value) && in_array("__toString", get_class_methods($value)))
        return strval($value->__toString());
    else
        return strval($value);
}

?>

kendsnyder+phpnet at gmail dot com (02-Jun-2007 06:08)

The only way to convert a large float to a string is to use printf('%0.0f',$float); instead of strval($float); (php 5.1.4).

// strval() will lose digits around pow(2,45);
echo pow(2,50); // 1.1258999068426E+015
echo (string)pow(2,50); // 1.1258999068426E+015
echo strval(pow(2,50)); // 1.1258999068426E+015

// full conversion
printf('%0.0f',pow(2,50)); // 112589906846624
echo sprintf('%0.0f',pow(2,50)); // 112589906846624

portos_ze_retour at hotmail dot fr (10-Mar-2006 04:15)

In complement to Tom Nicholson's contribution, here is the french version (actually it's possible to change the language, but you should check the syntax ;) )

function int_to_words($x) {
   global $nwords;

   if(!is_numeric($x))
     $w = '#';
   else if(fmod($x, 1) != 0)
     $w = '#';
   else {
     if($x < 0) {
         $w = $nwords['minus'].' ';
         $x = -$x;
     } else
         $w = '';
     // ... now $x is a non-negative integer.

     if($x < 21)  // 0 to 20
         $w .= $nwords[$x];
     else if($x < 100) {  // 21 to 99
         $w .= $nwords[10 * floor($x/10)];
         $r = fmod($x, 10);
         if($r > 0)
           $w .= '-'. $nwords[$r];
     } else if($x < 1000) {  // 100 to 999
         $w .= $nwords[floor($x/100)] .' '.$nwords['hundred'];
         $r = fmod($x, 100);
         if($r > 0)
           $w .= ' '.$nwords['separator'].' '. int_to_words($r);
     } else if($x < 1000000) {  // 1000 to 999999
         $w .= int_to_words(floor($x/1000)) .' '.$nwords['thousand'];
         $r = fmod($x, 1000);
         if($r > 0) {
           $w .= ' ';
           if($r < 100)
               $w .= $nwords['separator'].' ';
           $w .= int_to_words($r);

         }
     } else {    //  millions
         $w .= int_to_words(floor($x/1000000)) .' '.$nwords['million'];
         $r = fmod($x, 1000000);
         if($r > 0) {
           $w .= ' ';
           if($r < 100)
               $word .= $nwords['separator'].' ';
           $w .= int_to_words($r);
         }
     }
   }
   return $w;
}

 // Usage in English
$nwords = array( "zero", "one", "two", "three", "four", "five", "six", "seven",
                   "eight", "nine", "ten", "eleven", "twelve", "thirteen",
                   "fourteen", "fifteen", "sixteen", "seventeen", "eighteen",
                   "nineteen", "twenty", 30 => "thirty", 40 => "forty",
                   50 => "fifty", 60 => "sixty", 70 => "seventy", 80 => "eighty",
                   90 => "ninety" , "hundred" => "hundred", "thousand"=> "thousand", "million"=>"million",
                   "separator"=>"and", "minus"=>"minus");

echo 'There are currently '. int_to_words(-120223456) . ' members logged on.<br>';

 //Utilisation en Francais
$nwords = array( "zéro", "un", "deux", "trois", "quatre", "cinq", "six", "sept",
                   "huit", "neuf", "dix", "onze", "douze", "treize",
                   "quatorze", "quinze", "seize", "dix-sept", "dix-huit",
                   "dix-neuf", "vingt", 30 => "trente", 40 => "quarante",
                   50 => "cinquante", 60 => "soixante", 70 => "soixante-dix", 80 => "quatre-vingt",
                   90 => "quatre-vingt-dix" , "hundred" => "cent", "thousand"=> "mille", "million"=>"million",
                   "separator"=>"", "minus"=>"moins");

echo 'Il y a actuellement '. int_to_words(-120223456) . ' membres connectés.<br>';

anthony dot parsons at manx dot net (09-Jan-2006 05:59)

If you have to compare object variables like this be careful not to make a typo, or you could end up calling __set() -
<?php
/* Does what you'd expect it to */
if ( $user->password == $user2->password )

/* Doesn't */
if ( $user->password = $user2->password )
?>

To avoid that ever happening, do it like this:
<?php
if ( strval($user->password) == $user2->password )
?>

php at ianco dot co dot uk (07-Oct-2005 12:36)

I can't help being surprised that

(string)"0" == (string)"0.00"

evaluates to true. It's the same with strval and single quotes.
=== avoids it.

Why does it matter? One of my suppliers, unbelievably, uses 0 to mean standard discount and 0.00 to mean no discount in their stock files.

Steve Ball (09-Sep-2005 03:18)

It seems that one is being treated as an unsigned large int (32 bit), and the other as a signed large int (which has rolled over/under).

2326201276 - (-1968766020) =  4294967296.

brettsg at serialio dot com (02-Aug-2005 05:07)

How come this code in version 4.4 does something different than in version 4.3?

$val = 538759009 ^ 0xAABBCCDD;
print "val=" . $val;

= 2326201276 (version 4.4)

and

= -1968766020 (version 4.3)

Redbeard (24-Aug-2004 10:40)

You can also use the PEAR package Numbers_Words, which handles many other languages.

Tom Nicholson (28-Apr-2004 05:13)

If you want to convert an integer into an English word string, eg. 29 -> twenty-nine, then here's a function to do it.

Note on use of fmod()
  I used the floating point fmod() in preference to the % operator, because % converts the operands to int, corrupting values outside of the range [-2147483648, 2147483647]

I haven't bothered with "billion" because the word means 10e9 or 10e12 depending who you ask.

The function returns '#' if the argument does not represent a whole number.

<?php
$nwords = array( "zero", "one", "two", "three", "four", "five", "six", "seven",
                   "eight", "nine", "ten", "eleven", "twelve", "thirteen",
                   "fourteen", "fifteen", "sixteen", "seventeen", "eighteen",
                   "nineteen", "twenty", 30 => "thirty", 40 => "forty",
                   50 => "fifty", 60 => "sixty", 70 => "seventy", 80 => "eighty",
                   90 => "ninety" );

function int_to_words($x) {
   global $nwords;

   if(!is_numeric($x))
      $w = '#';
   else if(fmod($x, 1) != 0)
      $w = '#';
   else {
      if($x < 0) {
         $w = 'minus ';
         $x = -$x;
      } else
         $w = '';
      // ... now $x is a non-negative integer.

      if($x < 21)   // 0 to 20
         $w .= $nwords[$x];
      else if($x < 100) {   // 21 to 99
         $w .= $nwords[10 * floor($x/10)];
         $r = fmod($x, 10);
         if($r > 0)
            $w .= '-'. $nwords[$r];
      } else if($x < 1000) {   // 100 to 999
         $w .= $nwords[floor($x/100)] .' hundred';
         $r = fmod($x, 100);
         if($r > 0)
            $w .= ' and '. int_to_words($r);
      } else if($x < 1000000) {   // 1000 to 999999
         $w .= int_to_words(floor($x/1000)) .' thousand';
         $r = fmod($x, 1000);
         if($r > 0) {
            $w .= ' ';
            if($r < 100)
               $w .= 'and ';
            $w .= int_to_words($r);
         }
      } else {    //  millions
         $w .= int_to_words(floor($x/1000000)) .' million';
         $r = fmod($x, 1000000);
         if($r > 0) {
            $w .= ' ';
            if($r < 100)
               $word .= 'and ';
            $w .= int_to_words($r);
         }
      }
   }
   return $w;
}

?>

Usage:
<?php
echo 'There are currently '. int_to_words($count) . ' members logged on.';
?>