$i2？ =? " 122456789 10";

Echo? (floating point) $i? -? (float)$ I2； ? //The output result is correct.

$i？ =? " 123456789 10";

$i2？ =? " 122456789 10";

Echo? (int)$i？ -? (int)$ I2； //The output result is 0,? Because the maximum value of int type is 27 ..., these two values are the same after int conversion.