php - 如何生成随机正负小数？

Question

如何使用 php rand() 或其他方法重新生成从 -0.0010 到 0.0010 的随机小数？

Answer 1

将rand()除以最大随机数，乘以范围并加上起始数:

<?php
  // rand()/getrandmax() gives a float number between 0 and 1
  // if you multiply it by 0.002 you'll get a number between 0 and 0.002
  // add the starting number -0.001 and you'll get a number between -0.001 and 0.001

  echo rand()/getrandmax()*0.002-0.001;
?>