{"id":56,"date":"2026-09-15T00:00:00","date_gmt":"2026-09-14T15:00:00","guid":{"rendered":"https:\/\/pusyuuwanko.com\/wordpress\/?p=56"},"modified":"2026-10-09T20:17:45","modified_gmt":"2026-10-09T11:17:45","slug":"%e7%a2%ba%e5%ae%9f%e3%81%aband%e6%bc%94%e7%ae%97%e3%81%ab%e3%81%97%e3%81%a6%e3%82%8b%e3%81%ae%e3%81%abor%e6%bc%94%e7%ae%97%e3%81%ab%e3%81%aa%e3%81%a3%e3%81%9f%e7%90%86%e7%94%b1%e3%81%af%e4%bd%95","status":"publish","type":"post","link":"https:\/\/p-blog.pusyuuwanko.com\/index.php\/2026\/09\/15\/%e7%a2%ba%e5%ae%9f%e3%81%aband%e6%bc%94%e7%ae%97%e3%81%ab%e3%81%97%e3%81%a6%e3%82%8b%e3%81%ae%e3%81%abor%e6%bc%94%e7%ae%97%e3%81%ab%e3%81%aa%e3%81%a3%e3%81%9f%e7%90%86%e7%94%b1%e3%81%af%e4%bd%95\/","title":{"rendered":"\u78ba\u5b9f\u306band&&\u6f14\u7b97\u306b\u3057\u3066\u308b\u306e\u306bor||\u6f14\u7b97\u306b\u306a\u3063\u305f\u7406\u7531\u306f\u4f55\u3060\u3063\u305f\u306e\u304b\u306b\u3064\u3044\u3066"},"content":{"rendered":"

\u78ba\u5b9f\u306band&&\u6f14\u7b97\u306b\u3057\u3066\u308b\u306e\u306bor||\u6f14\u7b97\u306b\u306a\u3063\u305f\u7406\u7531\u306f\u4f55\u3060\u3063\u305f\u306e\u304b\u306b\u3064\u3044\u3066<\/h2>\n

!($x === 0 && $x === null)<\/code> \u304c\u5e38\u306b true \u306b\u306a\u3063\u305f\u8a71<\/p>\n

PHP\u3067\u6761\u4ef6\u5f0f\u3092\u66f8\u3044\u3066\u3044\u3066\u3001\u300c\u660e\u3089\u304b\u306b false \u306b\u306a\u308b\u306f\u305a\u306e\u5f0f\u304c true \u3092\u8fd4\u3059\u300d\u3068\u3044\u3046\u5834\u9762\u306b\u51fa\u304f\u308f\u3057\u305f\u3002\u539f\u56e0\u306f\u30c9\u30fb\u30e2\u30eb\u30ac\u30f3\u306e\u6cd5\u5247\u3060\u3063\u305f\u306e\u3060\u304c\u3001\u7d50\u8ad6\u306b\u305f\u3069\u308a\u7740\u304f\u307e\u3067\u306b\u4f55\u6bb5\u968e\u304b\u52d8\u9055\u3044\u3092\u8e0f\u3093\u3060\u306e\u3067\u3001\u305d\u306e\u904e\u7a0b\u3092\u305d\u306e\u307e\u307e\u8a18\u9332\u3057\u3066\u304a\u304f\u3002<\/p>\n

\n

1. \u767a\u7aef<\/h2>\n

\u3042\u308b\u5909\u6570\u304c\u300c0 \u3067\u3082 null \u3067\u3082\u306a\u3044\u300d\u3053\u3068\u3092\u78ba\u8a8d\u3057\u305f\u304b\u3063\u305f\u3002\u3053\u3046\u66f8\u3044\u305f\u3002<\/p>\n

!($nowNotification === 0 && $nowNotification === null)<\/code><\/pre>\n
\u52d5\u4f5c\u78ba\u8a8d\u306e\u305f\u3081\u3001\u6bd4\u8f03\u306e\u9014\u4e2d\u7d4c\u904e\u3082\u4e26\u3079\u3066\u51fa\u529b\u3057\u3066\u307f\u305f\u3002<\/p>\n
print_r(\n    !($nowNotification === 0) . \"\u3068\" .\n    !($nowNotification === null) . \"\u3068\" .\n    !($nowNotification === 0 && $nowNotification === null)\n);<\/code><\/pre>\n
\u51fa\u529b\u306f\u3053\u3046\u306a\u3063\u305f\u3002<\/p>\n
1\u3068\u30681<\/code><\/pre>\n
\n
2. \u6700\u521d\u306e\u7591\u554f<\/h2>\n
PHP\u3067\u306f\u771f\u507d\u5024\u3092\u6587\u5b57\u5217\u9023\u7d50\u3059\u308b\u3068\u3001true<\/code> \u306f \"1\"<\/code>\u3001false<\/code> \u306f \"\"<\/code>\uff08\u7a7a\u6587\u5b57\uff09\u306b\u306a\u308b\u3002\u3053\u306e\u6319\u52d5\u81ea\u4f53\u306f\u77e5\u3063\u3066\u3044\u305f\u306e\u3067\u3001\u51fa\u529b\u306f\u6b21\u306e\u3088\u3046\u306b\u8aad\u3081\u308b\u3002<\/p>\n\n\n\n\n\n\n\n
\u5f0f<\/th>\n\u7d50\u679c<\/th>\n<\/tr>\n<\/thead>\n
!($x === 0)<\/code><\/td>\ntrue \u2192 1<\/code><\/td>\n<\/tr>\n
!($x === null)<\/code><\/td>\nfalse \u2192 “<\/td>\n<\/tr>\n
!($x === 0 && $x === null)<\/code><\/td>\ntrue \u2192 1<\/code><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
\u3053\u3053\u304b\u3089\u5909\u6570\u306e\u4e2d\u8eab\u304c null<\/code> \u3067\u3042\u308b\u3053\u3068\u306f\u5206\u304b\u3063\u305f\u3002\u5206\u304b\u3089\u306a\u304b\u3063\u305f\u306e\u306f3\u3064\u76ee\u3060\u3002<\/p>\n
1 \u3068 0 \u3092 &&<\/code> \u3067\u7e4b\u3044\u3060\u306e\u306b\u3001\u306a\u305c 1 \u304c\u8fd4\u308b\u306e\u304b\u3002<\/strong><\/p>\n
false && true<\/code> \u306f false<\/code> \u306e\u306f\u305a\u3067\u3001\u671f\u5f85\u3057\u3066\u3044\u305f\u306e\u306f false<\/code> \u3060\u3063\u305f\u3002\u3057\u304b\u3057\u8fd4\u3063\u3066\u304d\u305f\u306e\u306f true<\/code>\u3002\u3057\u304b\u3082\u3053\u306e\u8fd4\u308a\u65b9\u3001\u3069\u3053\u304b\u3067\u898b\u305f\u3053\u3068\u304c\u3042\u308b\u3002\u307e\u308b\u3067 or<\/code> \u306e\u3088\u3046\u306a\u6319\u52d5<\/strong>\u3060\u3063\u305f\u3002or<\/code> \u306b\u3057\u305f\u3064\u3082\u308a\u306f\u4e00\u5207\u306a\u3044\u306e\u306b\u3002<\/p>\n
\n
3. \u52d8\u9055\u3044\u305d\u306e1 \u2014 !<\/code> \u304c\u5c4a\u304f\u7bc4\u56f2<\/h2>\n
\u6700\u521d\u306e\u8aa4\u308a\u306f\u3053\u3053\u3060\u3063\u305f\u30021\u3064\u76ee\u30682\u3064\u76ee\u306e\u51fa\u529b\uff081<\/code> \u3068\u7a7a\u6587\u5b57\uff09\u3092 &&<\/code> \u3067\u7e4b\u3044\u3060\u7d50\u679c\u304c3\u3064\u76ee\u3060\u3068\u601d\u3044\u8fbc\u3093\u3067\u3044\u305f\u3002<\/p>\n
\u3057\u304b\u3057 !<\/code> \u306f\u30ab\u30c3\u30b3\u306e\u5916<\/strong>\u306b\u3042\u308b\u3002\u95a2\u6570\u3068\u5f15\u6570\u306e\u5f62\u306b\u7f6e\u304d\u63db\u3048\u308b\u3068\u3001\u4f55\u304c\u8d77\u304d\u3066\u3044\u308b\u304b\u304c\u306f\u3063\u304d\u308a\u3059\u308b\u3002<\/p>\n
\/\/ \u79c1\u304c\u60f3\u5b9a\u3057\u3066\u3044\u305f\u3082\u306e\nand( not(A), not(B) )\n\n\/\/ \u5b9f\u969b\u306b\u66f8\u3044\u3066\u3044\u305f\u3082\u306e\nnot( and(A, B) )<\/code><\/pre>\n
not<\/code> \u306f\u5f15\u6570\u30921\u3064\u3057\u304b\u53d6\u3089\u306a\u3044\u3002\u53d7\u3051\u53d6\u308b\u306e\u306f and<\/code> \u304c\u307e\u3068\u3081\u305f\u7b54\u30481\u500b\u3060\u3051\u3067\u3001\u5185\u5074\u306e A \u3084 B \u306b\u306f\u624b\u304c\u5c4a\u304b\u306a\u3044\u3002\u305d\u308c\u305e\u308c\u3092\u500b\u5225\u306b\u53cd\u8ee2\u3057\u3066\u56de\u308b\u52d5\u304d\u306f\u3057\u306a\u3044\u3002<\/strong><\/p>\n
\u5b9f\u969b\u306e\u8a08\u7b97\u306f\u3053\u3046\u3060\u3063\u305f\u3002<\/p>\n
A: $x === 0     \u2192 false\nB: $x === null  \u2192 true\n\nand(false, true) \u2192 false\nnot(false)       \u2192 true   \u2190 \u3053\u308c\u304c\u51fa\u529b\u3055\u308c\u305f 1<\/code><\/pre>\n
1\u3064\u76ee\u30fb2\u3064\u76ee\u306b\u8868\u793a\u3055\u308c\u3066\u3044\u305f\u5024\u306f not<\/code> \u3092\u901a\u3057\u305f\u5f8c<\/strong>\u306e\u5024\u3067\u30013\u3064\u76ee\u306e\u5185\u5074\u3067\u4f7f\u308f\u308c\u3066\u3044\u308b\u306e\u306f not<\/code> \u3092\u901a\u3059\u524d<\/strong>\u306e\u5024\u3002\u52a0\u5de5\u5f8c\u306e\u7d50\u679c\u3068\u6750\u6599\u3092\u53d6\u308a\u9055\u3048\u3066\u3044\u305f\u3002<\/p>\n
\n
4. \u52d8\u9055\u3044\u305d\u306e2 \u2014 &&<\/code> \u306e\u65e5\u672c\u8a9e\u8a33<\/h2>\n
\u305d\u3082\u305d\u3082\u5f0f\u306e\u610f\u5473\u81ea\u4f53\u3082\u30ba\u30ec\u3066\u3044\u305f\u3002<\/p>\n
\u65e5\u672c\u8a9e\u3067\u300c0 \u3068 null \u306e\u5834\u5408\u300d\u3068\u8a00\u3046\u3068\u3001\u3075\u3064\u3046\u306f2\u3064\u306e\u30b1\u30fc\u30b9\u3092\u4e26\u3079\u3066\u3044\u308b<\/strong>\u610f\u5473\u306b\u306a\u308b\u3002\u3057\u304b\u3057 &&<\/code> \u306f\u305d\u3046\u3044\u3046\u610f\u5473\u3067\u306f\u306a\u3044\u3002&&<\/code> \u304c\u805e\u3044\u3066\u3044\u308b\u306e\u306f\u3001\u305f\u3063\u305f1\u500b\u306e\u5024\u306b\u3064\u3044\u3066\u306e1\u56de\u304d\u308a\u306e\u8cea\u554f\u3060\u3002<\/p>\n
\n
$x<\/code> \u306e\u4e2d\u8eab\u306f\u30010 \u3067\u3042\u308a\u3001\u304b\u3064\u540c\u6642\u306b<\/strong> null \u3067\u3082\u3042\u308b\u304b\uff1f<\/p>\n<\/blockquote>\n
===<\/code> \u306f\u578b\u307e\u3067\u542b\u3081\u305f\u53b3\u5bc6\u6bd4\u8f03\u306a\u306e\u3067\u3001\u3042\u308b\u5024\u304c\u300cint \u306e 0 \u3067\u3042\u308a\u306a\u304c\u3089\u540c\u6642\u306b null\u300d\u306b\u306a\u308b\u3053\u3068\u306f\u7d76\u5bfe\u306b\u306a\u3044\u3002\u3064\u307e\u308a\u5185\u5074\u306e and<\/code> \u306f $x<\/code> \u306b\u4f55\u304c\u5165\u3063\u3066\u3044\u3066\u3082\u5fc5\u305a false<\/strong>\u3002\u305d\u308c\u3092\u5916\u306e !<\/code> \u304c\u53cd\u8ee2\u3059\u308b\u306e\u3067\u3001\u3053\u306e\u5f0f\u306f\u5e38\u306b true<\/strong> \u3092\u8fd4\u3059\u3002<\/p>\n
\u52d5\u3044\u3066\u3044\u308b\u3088\u3046\u306b\u898b\u3048\u3066\u3001\u5b9f\u969b\u306b\u306f\u4f55\u3082\u5224\u5b9a\u3057\u3066\u3044\u306a\u3044\u5f0f\u3060\u3063\u305f\u3002<\/p>\n
\n
5. \u6838\u5fc3 \u2014 \u53cd\u8ee2\u306f\u6f14\u7b97\u5b50\u306b\u3082\u53ca\u3076<\/h2>\n
\u305d\u3057\u3066\u300c\u307e\u308b\u3067 or<\/code> \u3060\u300d\u3068\u3044\u3046\u9055\u548c\u611f\u3002\u3042\u308c\u306f\u6b63\u3057\u304b\u3063\u305f\u3002\u5b9f\u969b\u306b or<\/code> \u306b\u5316\u3051\u3066\u3044\u305f\u3002<\/strong><\/p>\n
!<\/code> \u3092\u30ab\u30c3\u30b3\u306e\u4e2d\u306b\u914d\u308b\u3068\u3001\u4e2d\u306e\u5024\u3060\u3051\u3067\u306a\u304f\u6f14\u7b97\u5b50\u305d\u306e\u3082\u306e\u3082\u5165\u308c\u66ff\u308f\u308b<\/strong>\u3002<\/p>\n
!(A && B)   \u2261   !A || !B     \/\/ && \u304c || \u306b\u306a\u308b\n!(A || B)   \u2261   !A && !B     \/\/ || \u304c && \u306b\u306a\u308b<\/code><\/pre>\n
\u3044\u308f\u3086\u308b\u30c9\u30fb\u30e2\u30eb\u30ac\u30f3\u306e\u6cd5\u5247\u3060\u304c\u3001\u8eab\u8fd1\u306a\u4f8b\u3067\u8003\u3048\u308c\u3070\u76f4\u611f\u7684\u306b\u7d0d\u5f97\u3067\u304d\u308b\u3002<\/p>\n
\n
\u300c\u5098\u3068<\/strong>\u30ab\u30d0\u30f3\u306e\u4e21\u65b9<\/strong>\u3092\u6301\u3063\u3066\u3044\u308b\u300d<\/p>\n<\/blockquote>\n
\u3053\u308c\u3092\u5426\u5b9a\u3059\u308b\u3068\u300c\u5098\u3082\u30ab\u30d0\u30f3\u3082\u6301\u3063\u3066\u3044\u306a\u3044\u300d\u2026\u2026\u3067\u306f\u306a\u3044\u3002\u7247\u65b9\u3060\u3051\u5fd8\u308c\u305f\u4eba\u3082\u5426\u5b9a\u5074\u306b\u5165\u308b<\/strong>\u304b\u3089\u3060\u3002\u6b63\u3057\u304f\u306f\u3053\u3046\u306a\u308b\u3002<\/p>\n
\n
\u300c\u5098\u304c\u7121\u3044\u3001\u307e\u305f\u306f<\/strong> \u30ab\u30d0\u30f3\u304c\u7121\u3044\u300d<\/p>\n<\/blockquote>\n
\u300c\u4e21\u65b9\u305d\u308d\u3063\u3066\u3044\u308b\u300d\u306e\u53cd\u5bfe\u306f\u300c\u3069\u308c\u304b\u6b20\u3051\u3066\u3044\u308b\u300d\u3002\u6b20\u3051\u3066\u3044\u308b\u306e\u306f\u7247\u65b9\u3067\u8db3\u308a\u308b\u306e\u3067\u3001&&<\/code>\uff08\u4e21\u65b9\uff09\u304c ||<\/code>\uff08\u3069\u3061\u3089\u304b\uff09\u306b\u5909\u308f\u308b\u3002<\/p>\n
\u306a\u304a\u300c\u5098\u3082\u30ab\u30d0\u30f3\u3082\u6301\u3063\u3066\u3044\u306a\u3044\u300d\uff08!\u5098 && !\u30ab\u30d0\u30f3<\/code>\uff09\u3068\u3044\u3046\u5f0f\u81ea\u4f53\u306f\u6210\u7acb\u3059\u308b\u3057\u610f\u5473\u3082\u3042\u308b\u3002\u305f\u3060\u3057\u5143\u306e\u5426\u5b9a\u3068\u3057\u3066\u306f\u6761\u4ef6\u304c\u5f37\u3059\u304e\u308b<\/strong>\u3002\u7247\u65b9\u3060\u3051\u6301\u3063\u3066\u3044\u308b\u4eba\u304c\u524d\u8005\u306b\u306f\u542b\u307e\u308c\u308b\u306e\u306b\u5f8c\u8005\u304b\u3089\u306f\u6f0f\u308c\u308b\u306e\u3067\u3001\u30ab\u30d0\u30fc\u3059\u308b\u7bc4\u56f2\u304c\u9055\u3046\u3002<\/p>\n
\u3053\u308c\u3092\u81ea\u5206\u306e\u30b3\u30fc\u30c9\u306b\u5f53\u3066\u306f\u3081\u308b\u3068\u3001\u66f8\u3044\u3066\u3044\u305f\u5f0f\u306e\u6b63\u4f53\u306f\u3053\u3046\u3060\u3063\u305f\u3002<\/p>\n
!($x === 0 && $x === null)\n\/\/ \u2193 \u5c55\u958b\u3059\u308b\u3068\n$x !== 0 || $x !== null<\/code><\/pre>\n
$x<\/code> \u306b\u4f55\u304c\u5165\u3063\u3066\u3044\u3066\u3082\u3001\u3069\u3061\u3089\u304b\u7247\u65b9\u306f\u5fc5\u305a\u6210\u7acb\u3059\u308b\uff080 \u306a\u3089\u300cnull \u3058\u3083\u306a\u3044\u300d\u304c\u771f\u3001null \u306a\u3089\u300c0 \u3058\u3083\u306a\u3044\u300d\u304c\u771f\uff09\u3002\u3060\u304b\u3089\u3044\u3064\u3067\u3082 true\u3002or<\/code> \u306b\u898b\u3048\u305f\u306e\u3067\u306f\u306a\u304f\u3001or<\/code> \u3060\u3063\u305f\u3002<\/strong><\/p>\n
\n
6. \u6b63\u3057\u3044\u66f8\u304d\u65b9<\/h2>\n
\u300c0 \u3067\u3082 null \u3067\u3082\u306a\u3044\u300d\u3092\u5224\u5b9a\u3057\u305f\u3044\u306a\u3089\u3001\u3053\u3046\u3060\u3063\u305f\u3002<\/p>\n
$x !== 0 && $x !== null      \/\/ \u7d20\u76f4\u306b\u66f8\u304f\n!($x === 0 || $x === null)   \/\/ !\u3054\u3068\u5916\u306b\u51fa\u3059\u306a\u3089\u3001\u4e2d\u306f || \u306b\u306a\u308b<\/code><\/pre>\n
\u9006\u306b\u300c0 \u304b null \u306e\u3069\u3061\u3089\u304b\u3067\u3042\u308b\u300d\u306a\u3089\u3002<\/p>\n
$x === 0 || $x === null<\/code><\/pre>\n
\n
\u7d50\u8ad6<\/h2>\n
\u4eca\u56de\u3064\u307e\u305a\u3044\u305f\u539f\u56e0\u306f\u3001\u77e5\u8b58\u306e\u6b20\u843d\u3068\u3044\u3046\u3088\u308a\u60f3\u5b9a\u7bc4\u56f2\u306e\u72ed\u3055<\/strong>\u3060\u3063\u305f\u3002<\/p>\n