PHP floating point comparison method_php tips

The example in this article describes the method of PHP floating point comparison. Share it with everyone for your reference, the details are as follows:

<&#63;php
/**
 * 浮点数一般是不能用来比较大小的，但是我们可以用一种变通的的方式
 * 用var_dump输出浮点是看不出效果的,可以用serialize查看
 * 1.round 2.浮点转换成字符串
 *
 * 转换成字符串方法：
 * 通过在其前面加上(string)或用strval()函数来转变成 字符串
 * 在一个需要字符串的表达式中，字符串会自动转变，比如在使用函数 echo() 或 print() 时， 或在一个变量和一个 字符串 进行比较时，就会发生这种转变
 * true会转为1 ， 而false则会转为空字符串
 *
 */
$a = 13.2;
$b = 24;
$c = $a/$b;
//实际值是这个d:0.54999999999999993338661852249060757458209991455078125;
echo serialize($c).'<br/>';//
echo $c.'<br/>';//输出时会显示成0.55 实际的值是比他小的
//所以直接和0.55比较大小是不成立的
if($c == 0.55){
  echo 'nothing';
}
$c = round($c,2);
//用round处理
if($c == 0.55){
  echo 'ok';
}
echo "<br/>";
//强制转为字符串
// $c = (string)$c;
// $c = strval($c);
if("$c" == 0.55){
  echo 'ok';
}
&#63;>

The running results are as follows:

d:0.54999999999999993338661852249060757458209991455078125;
0.55
ok
ok

Readers who are interested in more PHP-related content can check out the special topics on this site: "Summary of PHP operations and operator usage", "Introduction to PHP basic syntax tutorial", " Summary of PHP error and exception handling methods" and "Summary of common PHP functions and techniques"

I hope this article will be helpful to everyone in PHP programming.