PHP浮点型

<?php
$num_float1 = 1.234;    //小数点
echo $num_float1;
echo "<br />";
$num_float2 = 1.2e3;    //科学计数法，小写e
echo $num_float2;
echo "<br />";
$num_float3 = 7E-3;     //科学计数法，大写E
echo $num_float3;
echo "<br />";
?>