Complex classes like ArrayList often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes. You can also have a look at the cohesion graph to spot any un-connected, or weakly-connected components.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
While breaking up the class, it is a good idea to analyze how other classes use ArrayList, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
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| 8 | class ArrayList implements ListInterface |
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| 9 | { |
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| 10 | /** @var array */ |
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| 11 | protected $items; |
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| 12 | |||
| 13 | /** |
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| 14 | * @param array|\Traversable $items |
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| 15 | */ |
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| 16 | 53 | public function __construct($items = []) |
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| 24 | |||
| 25 | /** |
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| 26 | * {@inheritdoc} |
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| 27 | */ |
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| 28 | 1 | public function __toString() |
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| 49 | |||
| 50 | /** |
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| 51 | * {@inheritdoc} |
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| 52 | */ |
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| 53 | 43 | public function toArray() |
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| 65 | |||
| 66 | /** |
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| 67 | * {@inheritdoc} |
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| 68 | */ |
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| 69 | 22 | public function all() |
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| 73 | |||
| 74 | /** |
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| 75 | * {@inheritdoc} |
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| 76 | */ |
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| 77 | 7 | public function count() |
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| 81 | |||
| 82 | /** |
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| 83 | * {@inheritdoc} |
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| 84 | */ |
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| 85 | 1 | function jsonSerialize() |
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| 89 | |||
| 90 | /** |
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| 91 | * {@inheritdoc} |
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| 92 | */ |
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| 93 | 49 | public function getIterator() |
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| 99 | |||
| 100 | /** |
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| 101 | * {@inheritdoc} |
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| 102 | */ |
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| 103 | 1 | public function offsetExists($offset) |
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| 107 | |||
| 108 | /** |
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| 109 | * {@inheritdoc} |
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| 110 | */ |
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| 111 | 4 | public function offsetGet($offset) |
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| 115 | |||
| 116 | /** |
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| 117 | * {@inheritdoc} |
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| 118 | */ |
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| 119 | 4 | public function offsetSet($offset, $value) |
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| 124 | |||
| 125 | /** |
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| 126 | * {@inheritdoc} |
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| 127 | */ |
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| 128 | 1 | public function offsetUnset($offset) |
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| 132 | |||
| 133 | /** |
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| 134 | * {@inheritdoc} |
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| 135 | */ |
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| 136 | 1 | public function serialize() |
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| 140 | |||
| 141 | /** |
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| 142 | * {@inheritdoc} |
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| 143 | */ |
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| 144 | 1 | public function unserialize($serialized) |
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| 148 | |||
| 149 | /** |
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| 150 | * {@inheritdoc} |
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| 151 | */ |
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| 152 | public function clear() |
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| 156 | |||
| 157 | /** |
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| 158 | * {@inheritdoc} |
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| 159 | */ |
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| 160 | 3 | public function contains(...$values) |
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| 169 | |||
| 170 | /** |
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| 171 | * {@inheritdoc} |
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| 172 | */ |
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| 173 | 5 | public function get($key, $default = null) |
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| 177 | |||
| 178 | /** |
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| 179 | * {@inheritdoc} |
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| 180 | */ |
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| 181 | 6 | public function set($key, $value) |
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| 189 | |||
| 190 | /** |
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| 191 | * {@inheritdoc} |
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| 192 | */ |
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| 193 | 2 | public function remove(...$keys) |
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| 200 | |||
| 201 | /** |
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| 202 | * {@inheritdoc} |
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| 203 | */ |
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| 204 | 1 | public function has(...$keys) |
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| 213 | |||
| 214 | /** |
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| 215 | * {@inheritdoc} |
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| 216 | */ |
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| 217 | 1 | public function filter(callable $handler = null) |
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| 228 | |||
| 229 | /** |
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| 230 | * {@inheritdoc} |
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| 231 | */ |
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| 232 | 3 | public function map(callable $handler) |
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| 236 | |||
| 237 | /** |
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| 238 | * {@inheritdoc} |
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| 239 | */ |
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| 240 | 1 | public function reduce(callable $handler, $initial = null) |
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| 247 | |||
| 248 | /** |
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| 249 | * {@inheritdoc} |
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| 250 | */ |
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| 251 | 2 | public function groupBy(callable $handler) |
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| 263 | |||
| 264 | /** |
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| 265 | * {@inheritdoc} |
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| 266 | */ |
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| 267 | 2 | public function keyBy(callable $handler) |
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| 276 | |||
| 277 | /** |
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| 278 | * {@inheritdoc} |
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| 279 | */ |
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| 280 | 4 | public function combine(ListInterface $list) |
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| 284 | |||
| 285 | /** |
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| 286 | * {@inheritdoc} |
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| 287 | */ |
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| 288 | 2 | public function first(callable $handler = null, $default = null) |
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| 300 | |||
| 301 | /** |
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| 302 | * {@inheritdoc} |
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| 303 | */ |
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| 304 | 2 | public function last(callable $handler = null, $default = null) |
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| 319 | |||
| 320 | /** |
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| 321 | * {@inheritdoc} |
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| 322 | */ |
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| 323 | 8 | public function intersect(ListInterface $list) |
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| 327 | |||
| 328 | /** |
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| 329 | * {@inheritdoc} |
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| 330 | */ |
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| 331 | 4 | public function union(ListInterface $list) |
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| 335 | |||
| 336 | /** |
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| 337 | * {@inheritdoc} |
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| 338 | */ |
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| 339 | 4 | public function merge(ListInterface $list) |
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| 343 | |||
| 344 | /** |
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| 345 | * {@inheritdoc} |
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| 346 | */ |
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| 347 | 2 | public function implode($glue = null) |
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| 351 | |||
| 352 | /** |
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| 353 | * {@inheritdoc} |
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| 354 | */ |
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| 355 | 2 | public function isEmpty() |
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| 359 | |||
| 360 | /** |
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| 361 | * {@inheritdoc} |
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| 362 | */ |
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| 363 | 3 | public function pop() |
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| 367 | |||
| 368 | /** |
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| 369 | * {@inheritdoc} |
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| 370 | */ |
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| 371 | 1 | public function push(...$values) |
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| 376 | |||
| 377 | /** |
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| 378 | * {@inheritdoc} |
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| 379 | */ |
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| 380 | 1 | public function shift() |
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| 384 | |||
| 385 | /** |
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| 386 | * {@inheritdoc} |
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| 387 | */ |
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| 388 | 1 | public function unshift(...$values) |
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| 393 | |||
| 394 | /** |
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| 395 | * {@inheritdoc} |
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| 396 | */ |
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| 397 | 2 | public function reverse() |
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| 401 | |||
| 402 | /** |
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| 403 | * {@inheritdoc} |
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| 404 | */ |
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| 405 | 2 | public function shuffle() |
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| 411 | |||
| 412 | /** |
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| 413 | * {@inheritdoc} |
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| 414 | */ |
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| 415 | 1 | public function sort(callable $callback = null) |
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| 425 | |||
| 426 | /** |
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| 427 | * {@inheritdoc} |
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| 428 | */ |
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| 429 | 2 | public function slice($offset, $length = null) |
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| 433 | |||
| 434 | /** |
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| 435 | * {@inheritdoc} |
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| 436 | */ |
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| 437 | 4 | public function splice($offset, $length = null, $replacement = null) |
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| 444 | |||
| 445 | /** |
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| 446 | * {@inheritdoc} |
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| 447 | */ |
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| 448 | 1 | public function unique() |
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| 452 | |||
| 453 | /** |
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| 454 | * @param mixed $value |
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| 455 | * @param string $method |
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| 456 | * @param int $order |
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| 457 | */ |
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| 458 | 4 | private function assertIsNullOrIntegerLessSize($value, $method, $order = 1) |
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| 473 | } |
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| 474 |
In PHP, under loose comparison (like
==, or!=, orswitchconditions), values of different types might be equal.For
integervalues, zero is a special case, in particular the following results might be unexpected: