ポケモンタイプ相性表

参考
https://www.pokemon.co.jp/ex/sun_moon/fight/161215_01.html

ポケモンの防御側から見たタイプ相性表です

例：ギャラドス 水・飛行タイプ

["×4"]=>電気
["×0.5"]=>炎・水・格闘・鋼
["×0"]=>地面

コード

<?php

function getTypeDefenseTable(...$typeIds) {
    // 引数が空またはnullの場合はnullを返す
    if (empty($typeIds) || (count($typeIds) === 1 && (is_null($typeIds[0]) || $typeIds[0] === ''))) {
        return null;
    }
    
    // 引数が1つで文字列（カンマ区切り）の場合は配列に変換
    if (count($typeIds) === 1 && is_string($typeIds[0]) && strpos($typeIds[0], ',') !== false) {
        $typeIds = array_map('intval', explode(',', $typeIds[0]));
    }
    
    // 有効なタイプIDが存在しない場合はnullを返す
    $validTypeIds = array_filter($typeIds, function($id) {
        return is_numeric($id) && $id >= 1 && $id <= 18;
    });
    if (empty($validTypeIds)) {
        return null;
    }
    
    // 有効なタイプIDのみを使用
    $typeIds = array_map('intval', $validTypeIds);
    
    // 防御側から見た倍率
    $defenseChart = [
     1 => ['×2' => [7],           '×0.5' => [], '×0' => [14]], // ノーマル
     2 => ['×2' => [3,9,13],      '×0.5' => [2,5,6,12,17,18], '×0' => []], // ほのお
     3 => ['×2' => [4,5],         '×0.5' => [2,3,6,17],       '×0' => []], // みず
     4 => ['×2' => [9],           '×0.5' => [4, 10, 17],      '×0' => []], // でんき
     5 => ['×2' => [2,6,8,10,12], '×0.5' => [3,4,5,9],        '×0' => []], // くさ
     6 => ['×2' => [2,7,13,17],   '×0.5' => [6],              '×0' => []], // こおり
     7 => ['×2' => [10,11,18],    '×0.5' => [12,13,16],     '×0' => []], // かくとう
     8 => ['×2' => [9,11],        '×0.5' => [5,8,12,17,18], '×0' => []], // どく
     9 => ['×2' => [3,5,6],       '×0.5' => [8,13],          '×0' => [4]], // じめん
     10 => ['×2' => [4,6,13],     '×0.5' => [5,7,13],       '×0' => [9]], // ひこう
     11 => ['×2' => [12,14,16],   '×0.5' => [7,11],          '×0' => []], // エスパー
     12 => ['×2' => [2,10,13],    '×0.5' => [5,7,9],        '×0' => []], // むし
     13 => ['×2' => [3,5,7,9,17], '×0.5' => [1,2,8,10],       '×0' => []], // いわ
     14 => ['×2' => [14,16],      '×0.5' => [8,12],          '×0' => [1]], // ゴースト
     15 => ['×2' => [6,15,18],    '×0.5' => [2,3,4,5],     '×0' => []], // ドラゴン
     16 => ['×2' => [7,12,18],    '×0.5' => [14,16],         '×0' => [11]], // あく
     17 => ['×2' => [2,7,9],      '×0.5' => [1,5,6,10,11,12,13,15,17,18], '×0' => [8]],//鋼
     18 => ['×2' => [8,17],       '×0.5' => [7,12,16], '×0' => [15]] // フェアリー
    ];

    $typeNames = [
        1 => 'ノーマル', 2 => 'ほのお', 3 => 'みず', 4 => 'でんき', 5 => 'くさ',
        6 => 'こおり', 7 => 'かくとう', 8 => 'どく', 9 => 'じめん', 10 => 'ひこう',
        11 => 'エスパー', 12 => 'むし', 13 => 'いわ', 14 => 'ゴースト', 15 => 'ドラゴン',
        16 => 'あく', 17 => 'はがね', 18 => 'フェアリー'
    ];

    // 攻撃タイプごとに最終倍率を計算
    $finalMultipliers = [];
    for ($atk = 1; $atk <= 18; $atk++) {
        $mult = 1.0;
        foreach ($typeIds as $defType) {
            if (!isset($defenseChart[$defType])) continue;
            $effect = $defenseChart[$defType];
            if (in_array($atk, $effect['×0'] ?? [])) {
                $mult = 0;
                break;
            }
            if (in_array($atk, $effect['×2'] ?? [])) $mult *= 2;
            if (in_array($atk, $effect['×0.5'] ?? [])) $mult *= 0.5;
        }
        $finalMultipliers[$atk] = $mult;
    }

    // 倍率ごとに分類
    $groups = [
        '×4' => [],
        '×2' => [],
        '×0.5' => [],
        '×0.25' => [],
        '×0' => []
    ];

    foreach ($finalMultipliers as $atk => $mult) {
        if ($mult == 4) $groups['×4'][] = $typeNames[$atk];
        elseif ($mult == 2) $groups['×2'][] = $typeNames[$atk];
        elseif ($mult == 0.5) $groups['×0.5'][] = $typeNames[$atk];
        elseif ($mult == 0.25) $groups['×0.25'][] = $typeNames[$atk];
        elseif ($mult == 0) $groups['×0'][] = $typeNames[$atk];
    }

    // HTML生成

    return $groups;
}




echo('<pre>');var_dump(getTypeDefenseTable(3,10));echo('</pre>');

結果

array(5) {
  ["×4"]=>
  array(1) {
    [0]=>
    string(9) "でんき"
  }
  ["×2"]=>
  array(0) {
  }
  ["×0.5"]=>
  array(4) {
    [0]=>
    string(9) "ほのお"
    [1]=>
    string(6) "みず"
    [2]=>
    string(12) "かくとう"
    [3]=>
    string(9) "はがね"
  }
  ["×0.25"]=>
  array(0) {
  }
  ["×0"]=>
  array(1) {
    [0]=>
    string(9) "じめん"
  }
}