寻找循环或其他东西，只是想摆脱所有这些如果，使代码更小 - looking for loop or something else ,just want to get rid of all these if, to make the code smaller

looking for loop or something else ,just want to get rid of all these if, to make the code smaller

  $num = 1
 if ($unix[9] == $num) {   
 $out[0] = $letters[1];
}
 if ($unix[9] == $num + 1) { 
 $out[1] = $letters[2];``
}
 if ($unix[9] == $num + 2) {
 $out[2] = $letters[3];
}
 if ($unix[9] == $num + 3) {
 $out[3] = $letters[4];
}
 if ($unix[9] == $num + 4) {
 $out[4] = $letters[5];
}
 if ($unix[9] == $num + 5) {
 $out[5] = $letters[6];
}
 if ($unix[9] == $num + 6) {
 $out[6] = $letters[7];
}
 if ($unix[9] == $num + 7) {
 $out[7] = $letters[8];
}
 if ($unix[9] == $num + 8) {
 $out[8] = $letters[9];
}

我正在寻找一个循环来避免上述行，或者其他东西来替换大多数 if 语句。

for($num = 1, $max = 9 ; $num < $max ; $num++){
  if ($unix[9] == $num) {   
     $out[$num] = $letters[$num + 1];
  }
}

$num = 1
for($i=1;$i<=9;i++) {
    if ($unix[9] == $num+($i-1)) {   
        $out[$i-1] = $letters[$i];
    }
}

这应该可以完成这项工作

for ($num = 1; $num < 9; $num++) {
    if ($unix[9] == $num) {
        $out[$num - 1] = $letters[$num];
    }
}