strval

(PHP 4, PHP 5, PHP 7)

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。

用户评论:

[#1] Hayley Watson [2007-08-21 20:53:49]

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

[#2] NyctoFixer at gmail dot com [2007-06-11 12:19:48]

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:

<?php 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); } ?>

[#3] kendsnyder+phpnet at gmail dot com [2007-06-01 22:08:56]

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

[#4] portos_ze_retour at hotmail dot fr [2006-03-10 08:15:10]

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( "z??ro", "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 connect??s.<br>';

[#5] anthony dot parsons at manx dot net [2006-01-09 09:59:26]

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

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

[#6] php at ianco dot co dot uk [2005-10-07 04:36:48]

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.

[#7] Steve Ball [2005-09-08 19:18:05]

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.

[#8] Tom Nicholson [2004-04-28 09:13:06]

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.'; ?>