1. php – Math functions

2. 常用數學函數 Function Description abs()
Returns the absolute value of a number
ceil()
Returns the value of a number rounded upwards to the nearest integer
floor()
Returns the value of a number rounded downwards to the nearest integer
is_nan()
Returns true if a value is not a number
lcg_value()
Returns a pseudo random number in the range of (0,1)
max()
Returns the number with the highest value of two specified numbers
min()
Returns the number with the lowest value of two specified numbers
pow()
Returns the value of x to the power of y
mt_rand()
Returns a random integer using Mersenne Twister algorithm
rand()
Returns a random integer
round()
Rounds a number to the nearest integer
sqrt()
Returns the square root of a number

3. 亂數 float lcg_value () int mt_rand(min, max) int rand(min, max)
產生介於0與1之浮點亂數
int mt_rand(min, max)
int rand(min, max)
產生介於min與max之整數亂數
<?php
echo lcg_value()."<br/>";
echo rand(1,49)."<br/>";
echo mt_rand(1,49)."<br/>";
?>

4. 四捨五入
<?php echo round(3.4); // 3 echo round(3.5); // 4 echo round(3.6); // 4 echo round(3.6, 0); // 4 echo round(3.6); // 4 echo round( , 2); // 1.96 echo round( , -3); // echo round(5.045, 2); // 5.05 echo round(5.055, 2); // 5.06 ?>

5. 二, 八, 十, 十六進位轉換 base_convert()
Converts a number from one base to another
bindec()
Converts a binary number to a decimal number
decbin()
Converts a decimal number to a binary number
dechex()
Converts a decimal number to a hexadecimal number
decoct()
Converts a decimal number to an octal number
hexdec()
Converts a hexadecimal number to a decimal number
octdec()
Converts an octal number to a decimal number