How to assign floating-point values
Using normal notation
<?php
$float_1 = 3.5; // Must contain a decimal point
$float_2 = -6.0; // May be negative
$float_3 = .125; // Same as 0.125
$float_4 = 1.; // Same as 1.0
?>
Using exponential notation
<?php
$exp_1 = 9.451e15; // Expands to 9.451 × 1015
$exp_2 = 6.022e+23; // Plus sign is optional
$exp_3 = 1.602e-19; // Exponent may be negative
$exp_4 = 9.806e0; // Exponent may be zero
$exp_5 = -1.759e11; // Mantissa may be negative
$exp_6 = 3e9; // Mantissa may be a whole number
?>