Using while loop to print 10-20 odd numbers on the screen, with <-> (exapmle 11-13-15-17-19, <-> not after 19).How to take the last number so as not to put a -. Thank you.

<?php

$x = 10;
while($x < 20){
   $x  ;
   if($x % 2){
      echo $x. "-";
   }
}

CodePudding user response：

As mentioned in the comments, have a boolean variable say firstTime. If this is true, don't prepend a hyphen, else if it is false, prepend it with a hyphen.

<?php

$x = 10;
$firstTime = true;
while($x < 20){
   $x  ;
   if($x % 2){
      echo ($firstTime ? "" : "-") . $x;
      $firstTime = false;
   }
}

CodePudding user response：

You can push the odd values to an array and after the loop you can convert the array to a string with the implode (https://www.php.net/manual/en/function.implode.php) function.

$x = 10;
$arr = [];
while($x<20){
  $x  ;
  if ($x%2){
    $arr[] = $x;
  }
}
echo implode(",", $arr);
// output will be a comma seperated string

CodePudding user response：

Turn the limit number into a variable and use a ternary operator to print out a dash only if $x 1 < $limit

https://paiza.io/projects/EDj6-u-FAcYxYoR7ON_cvg

<?php

$x = 10;
$y = 20;
while($x < $y){
   $x  ;
   if($x % 2){
      echo ($x   1 === $y) ? $x : $x. "-";
   }
}

?>

CodePudding user response：

Simple approach

Imagine you are printing a list of numbers from 10 to 20. If it's an even number, print the "-" symbol and if it's odd number, print the number.

<?php
$start = 10;
$end = 20;
while($start<$end)
{
  $n=$start;
  if($n>10)
  echo ($n%2==0)?"-":$n; //the gist is here
  $start  ;
}