php字符串转数字 (int)和intval对比

$str = “10”
intval(str) = 10 (int)str = 10
$str_1 = “10.5”
intval(str_1) = 10 (int)str = 10
$str_2 = “1,000”
intval(str_2) = 1 (int)str = 1
$int = 10
intval(int) = 10 (int)str = 10
$str_char = “b”
intval(str_char) = 0 (int)str = 0
$str_char_1 = “b10”
intval(str_char_1) = 0 (int)str = 0
$str_char_2 = “10b”
intval(str_char_2) = 10 (int)str = 10