text: <?php
  /* Prototype  : string strtr(string $str, string $from[, string $to]);
                  string strtr(string $str, array $replace_pairs);
   * Description: Translates characters in str using given translation tables
   * Source code: ext/standard/string.c
  */
  
  /* Testing strtr() function by passing the
   *   combination of numeric & regular strings for 'str' argument and
   *   corresponding translation pair of chars for 'from', 'to' & 'replace_pairs' arguments
  */
  
  echo "*** Testing strtr() : numeric & regular double quoted strings ***\n";
  /* definitions of required input variables */
  $count = 1;
  $heredoc_str = <<<EOD
  123
  abc
  1a2b3c
  EOD;
  //array of string inputs for $str
  $str_arr = array(
    //double quoted strings
    "123",
    "abc",
    "1a2b3c",
  
    //single quoted strings
    '123',
    'abc',
    '1a2b3c',
  
    //heredoc string
    $heredoc_str
  );
  $from = "123abc";
  $to = "abc123";
  $replace_pairs = array("1" => "a", "a" => 1, "2b3c" => "b2c3", "b2c3" => "3c2b");
  
  /* loop through to test strtr() with each element of $str_arr */
  for($index = 0; $index < count($str_arr); $index++) {
    echo "-- Iteration $count --\n";
  
    $str = $str_arr[$index];  //getting the $str_arr element in $str variable
  
    //strtr() call in three args syntax form
    var_dump( strtr($str, $from, $to) );
  
    //strtr() call in two args syntax form
    var_dump( strtr($str, $replace_pairs) );
  
    $count++;
  }
  echo "*** Done ***";
  ?>
  