如何生成随机正或负小数？

Question

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

Answer 1

除以rand()最大随机数,将其乘以范围并添加起始编号:

<?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;
?>