第四章 php数学运算
一.数值数据类型
数字或数值数据在PHP中一般就两种double和int。
PHP是一种松散类型的脚本语言,要注意类型转换的方式。
复制代码 代码如下:
$a = '5';
//数字的字符串也是数字,参与数学运算当数字处理
echo is_numeric ( $a ); //1
echo '
';
echo 7 + $a; //12
echo '
';
echo '7' + $a; //12
echo '
';
//用.连接后就按字符串处理
echo '7' . $a; //75
?>
二.随机数
Rand()函数是libc中定义的一个随机函数的简单包装器。
Mt_rand()函数是一个很好的代替实现。
复制代码 代码如下:
$a = rand(0,10);
echo $a;
echo '
';
echo getrandmax();
echo '
';
$b = mt_rand(0,10);
echo $b;
echo '
';
echo mt_getrandmax();
echo '
';
?>
output
1
32767
6
2147483647
三.格式化数据
复制代码 代码如下:
$a = 12345.6789;
//用于设置保留多少位小数点
echo number_format($a,2);
echo '
';
//也可以改变默认小数点的符号表示和千分位的表示符号
echo number_format($a,2,'#','*')
?>
Output
12,345.68
12*345#68
四.数学函数
函数 |
功能 |
Abs() |
取绝对值 |
Floor() |
舍去法取整 |
Ceil() |
进一法取整 |
Round() |
四舍五入 |
Min() |
求最小值或数组中最小值 |
Max() |
求最大值或数组中最大值 |
复制代码 代码如下:
$a = -123456.789;
$b = array (1, 2, 3, 4 );
echo abs ( $a );
echo '
';
echo floor ( $a );
echo '
';
echo ceil ( $a );
echo '
';
echo round ( $a );
echo '
';
echo min ( $b );
echo '
';
echo max ( $b );
?>
output
123456.789
-123457
-123456
-123457
1
4

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