php round 2e decimal to 0 or 5

Question

i want to round $t 2e decimal to 0 or 5.

 if $t= 1.31; //round to 1.30
 if $t= 1.32  //round to 1.30
 if $t= 1.33; //round to 1.35
 if $t= 1.34; //round to 1         


        

Answer 1

You can double the value so you can round to 1 decimal, then simple divide it by 2 again

$t = round(($t*2), 1) / 2;

Answer 2

try this one check the demo

0.05 * round($t * 20)

<?php
  $ts= [1.31, 1.32, 1.33, 1.34, 1.35, 1.36, 1.37, 1.38, 1.39, 1.40];
  array_walk($ts, function($t){echo number_format($t, 2)."\t".number_format(0.05*round($t*20), 2)."\n";});

output,

  1.31  1.30
1.32    1.30
1.33    1.35
1.34    1.35
1.35    1.35
1.36    1.35
1.37    1.35
1.38    1.40
1.39    1.40
1.40    1.40