php基础23：数值与数值函数

<?php

    //1.自动转换
    $a = 5;
    $b = "5a";
    $c = $a + $b;
    echo $c;
    echo "<br>";

    $a = 5;
    $b = "5a";
    $c = $a.$b;
    echo $c;
    echo "<br>";

    //1.（数值变量/数字字符串）检测
    $a = 5;
    $b = "5";
    $c = "123";
    echo is_numeric($a);
    echo "<br>";
    echo is_numeric($b);
    echo "<br>";

    //2. is_int() 和 is_float() is_double()

    //3.生成随机数 mt_rand()
    $num = mt_rand();
    echo $num;
    echo "<br>";
    $num1 = mt_rand(1, 100);
    echo $num1;
    echo "<br>";

    //4.数字格式化
    $num = 1234566776;
    echo number_format($num);
    echo "<br>";
    $num1 = 223445.2334;
    echo number_format($num1,2);
    echo "<br>";

    //5.数学函数、
    $number1 = -555;
    echo abs($number1);

?>