Complex classes like Collection 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 Collection, and based on these observations, apply Extract Interface, too.
1 | <?php |
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23 | class Collection implements ArrayAccess, Iterator, Countable, JsonSerializable |
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24 | { |
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25 | /** @var array */ |
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26 | protected $items; |
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27 | |||
28 | /** |
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29 | * Collection constructor. |
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30 | * |
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31 | * @param array $items |
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32 | */ |
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33 | 83 | public function __construct(array $items = []) |
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38 | |||
39 | /** |
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40 | * Generate a collection from an array of items. |
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41 | * I created this method so that it's possible to extend a collection more easily. |
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42 | * |
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43 | * @param array $items |
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44 | * |
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45 | * @todo call to_array on $items and don't require input to be an array. |
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46 | * |
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47 | * @return Collection |
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48 | */ |
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49 | 26 | public static function factory(array $items = []) |
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53 | |||
54 | /** |
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55 | * Get collection as an array |
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56 | * |
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57 | * @return array |
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58 | */ |
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59 | 41 | public function toArray() |
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63 | |||
64 | /** |
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65 | * Determine if collection has a given key |
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66 | * |
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67 | * @param mixed $key The key to look for |
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68 | * |
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69 | * @return bool |
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70 | */ |
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71 | 41 | public function has($key) |
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75 | |||
76 | /** |
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77 | * Does collection have item at position? |
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78 | * |
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79 | * Determine if collection has an item at a particular position (indexed from one). |
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80 | * Position can be positive and start from the beginning or it can be negative and |
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81 | * start from the end. |
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82 | * |
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83 | * @param int $position |
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84 | * |
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85 | * @return bool |
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86 | */ |
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87 | 2 | public function hasValueAt($position) |
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96 | |||
97 | /** |
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98 | * Get key at given position |
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99 | * |
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100 | * Returns the key at the given position, starting from one. Position can be positive (start from beginning) or |
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101 | * negative (start from the end). |
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102 | * |
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103 | * If the position does not exist, a RuntimeException is thrown. |
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104 | * |
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105 | * @param int $position |
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106 | * |
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107 | * @return string |
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108 | * |
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109 | * @throws RuntimeException |
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110 | */ |
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111 | 6 | public function getKeyAt($position) |
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125 | |||
126 | /** |
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127 | * Get value at given position |
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128 | * |
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129 | * Returns the value at the given position, starting from one. Position can be positive (start from beginning) or |
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130 | * negative (start from the end). |
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131 | * |
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132 | * If the position does not exist, a RuntimeException is thrown. |
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133 | * |
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134 | * @param int $position |
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135 | * |
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136 | * @return mixed |
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137 | * |
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138 | * @throws RuntimeException |
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139 | */ |
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140 | 2 | public function getValueAt($position) |
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144 | |||
145 | /** |
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146 | * Get the key of the first item found matching $item |
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147 | * |
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148 | * @todo Perhaps this should allow a callback in place of $item? |
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149 | * |
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150 | * @param mixed $item |
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151 | * |
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152 | * @return mixed|null |
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153 | */ |
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154 | 1 | public function keyOf($item) |
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164 | |||
165 | /** |
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166 | * Get the offset (index) of the first item found that matches $item |
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167 | * |
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168 | * @todo Perhaps this should allow a callback in place of $item? |
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169 | * |
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170 | * @param mixed $item |
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171 | * |
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172 | * @return int|null |
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173 | */ |
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174 | 1 | public function indexOf($item) |
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186 | |||
187 | /** |
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188 | * Get item by key, with an optional default return value |
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189 | * |
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190 | * @param mixed $key |
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191 | * @param mixed $default |
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192 | * |
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193 | * @return mixed |
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194 | */ |
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195 | 8 | public function get($key, $default = null) |
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203 | |||
204 | /** |
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205 | * Add an item with no regard to key |
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206 | * |
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207 | * @param mixed $value |
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208 | * |
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209 | * @return $this |
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210 | */ |
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211 | 5 | public function add($value) |
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217 | |||
218 | /** |
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219 | * Set an item at a given key |
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220 | * |
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221 | * @param mixed $key |
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222 | * @param mixed $value |
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223 | * @param bool $overwrite If false, do not overwrite existing key |
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224 | * |
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225 | * @return $this |
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226 | */ |
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227 | 12 | public function set($key, $value, $overwrite = true) |
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235 | |||
236 | /** |
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237 | * Delete an item by key |
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238 | * |
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239 | * @param mixed $key |
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240 | * |
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241 | * @return $this |
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242 | */ |
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243 | 3 | public function delete($key) |
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249 | |||
250 | /** |
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251 | * Clear the collection of all its items. |
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252 | * |
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253 | * @return $this |
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254 | */ |
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255 | 2 | public function clear() |
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261 | |||
262 | /** |
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263 | * Determine if collection contains given value |
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264 | * |
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265 | * @param mixed|callable $val |
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266 | * @param mixed $key |
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267 | * |
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268 | * @return bool |
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269 | */ |
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270 | 4 | public function contains($val, $key = null) |
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288 | |||
289 | /** |
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290 | * Fetch item from collection by key and remove it from collection |
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291 | * |
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292 | * @param mixed $key |
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293 | * |
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294 | * @return mixed |
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295 | */ |
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296 | 1 | public function pull($key) |
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304 | |||
305 | /** |
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306 | * Join collection items using a delimiter |
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307 | * |
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308 | * @param string $delim |
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309 | * |
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310 | * @return string |
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311 | */ |
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312 | 1 | public function join($delim = '') |
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316 | |||
317 | /** |
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318 | * Determine if collection has any items |
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319 | * |
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320 | * @return bool |
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321 | */ |
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322 | 4 | public function isEmpty() |
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326 | |||
327 | /** |
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328 | * Get a collection of only this collection's values (without its keys) |
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329 | * |
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330 | * @return Collection |
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331 | */ |
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332 | 1 | public function values() |
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336 | |||
337 | /** |
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338 | * Get a collection of only this collection's keys |
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339 | * |
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340 | * @return Collection |
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341 | */ |
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342 | 1 | public function keys() |
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346 | |||
347 | /** |
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348 | * Get a collection with order reversed |
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349 | * |
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350 | * @return Collection |
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351 | */ |
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352 | 6 | public function reverse() |
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356 | |||
357 | /** |
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358 | * Get a collection with keys and values flipped |
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359 | * |
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360 | * @return Collection |
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361 | */ |
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362 | 1 | public function flip() |
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370 | |||
371 | /** |
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372 | * Shuffle the order of this collection's values |
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373 | * |
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374 | * @return Collection |
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375 | */ |
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376 | 1 | public function shuffle() |
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381 | |||
382 | /** |
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383 | * Get a random value from the collection |
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384 | * |
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385 | * @return mixed |
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386 | */ |
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387 | 1 | public function random() |
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391 | |||
392 | /** |
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393 | * Sort the collection (using values) |
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394 | * |
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395 | * @param callable $alg |
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396 | * |
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397 | * @return $this |
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398 | */ |
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399 | 2 | public function sort(callable $alg = null) |
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409 | |||
410 | /** |
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411 | * Sort the collection (using keys) |
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412 | * |
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413 | * @param callable $alg |
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414 | * |
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415 | * @return $this |
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416 | */ |
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417 | 2 | public function ksort(callable $alg = null) |
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427 | |||
428 | /** |
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429 | * Append items to collection without regard to keys |
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430 | * |
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431 | * @param array|Traversable $items |
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432 | * |
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433 | * @return $this |
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434 | */ |
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435 | 2 | public function append($items) |
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447 | |||
448 | /** |
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449 | * Return first item or first item where callback returns true |
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450 | * |
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451 | * @param callable|null $callback |
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452 | * |
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453 | * @return mixed|null |
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454 | */ |
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455 | 7 | public function first(callable $callback = null) |
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466 | |||
467 | /** |
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468 | * Return last item or last item where callback returns true |
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469 | * |
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470 | * @param callable|null $callback |
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471 | * |
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472 | * @return mixed|null |
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473 | */ |
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474 | 3 | public function last(callable $callback = null) |
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478 | |||
479 | /** |
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480 | * Map collection |
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481 | * |
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482 | * Create a new collection using the results of a callback function on each item in this collection. |
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483 | * |
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484 | * @param callable $callback |
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485 | * |
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486 | * @return Collection |
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487 | */ |
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488 | 3 | public function map(callable $callback) |
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499 | |||
500 | /** |
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501 | * Combine collection with another traversable/collection |
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502 | * |
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503 | * Using this collection's keys, and the incoming collection's values, a new collection is created and returned. |
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504 | * |
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505 | * @param array|Traversable $items |
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506 | * |
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507 | * @return Collection |
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508 | */ |
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509 | 5 | public function combine($items) |
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522 | |||
523 | /** |
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524 | * Get a new collection with only distinct values |
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525 | * |
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526 | * @return Collection |
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527 | */ |
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528 | 1 | public function distinct() |
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539 | |||
540 | /** |
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541 | * Remove all duplicate values from collection in-place |
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542 | * |
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543 | * @return Collection |
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544 | */ |
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545 | 1 | public function deduplicate() |
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551 | |||
552 | /** |
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553 | * Return a new collection with only filtered keys/values |
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554 | * |
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555 | * The callback accepts value, key, index and should return true if the item should be added to the returned |
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556 | * collection |
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557 | * |
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558 | * @param callable $callback |
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559 | * |
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560 | * @return Collection |
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561 | */ |
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562 | 1 | public function filter(callable $callback) |
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574 | |||
575 | /** |
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576 | * Fold collection into a single value |
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577 | * |
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578 | * Loop through collection calling a callback function and passing the result to the next iteration, eventually |
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579 | * returning a single value. |
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580 | * |
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581 | * @param callable $callback |
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582 | * @param mixed $initial |
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583 | * |
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584 | * @return null |
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585 | */ |
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586 | 1 | public function fold(callable $callback, $initial = null) |
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596 | |||
597 | /** |
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598 | * Return a merge of this collection and $items |
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599 | * |
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600 | * @param array|Traversable $items |
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601 | * |
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602 | * @return Collection |
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603 | */ |
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604 | 3 | public function merge($items) |
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617 | |||
618 | /** |
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619 | * Create a new collection with a union of this collection and $items |
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620 | * |
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621 | * This method is similar to merge, except that existing items will not be overwritten. |
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622 | * |
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623 | * @param $items |
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624 | */ |
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625 | 2 | public function union($items) |
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638 | |||
639 | /** |
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640 | * Call callback for each item in collection, passively |
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641 | * |
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642 | * @param callable $callback |
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643 | * |
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644 | * @return $this |
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645 | */ |
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646 | 1 | public function each(callable $callback) |
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655 | |||
656 | /** |
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657 | * Assert callback returns $expected value for each item in collection. |
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658 | * |
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659 | * @todo This can be used to easily make methods like all($callback) and none($callback). |
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660 | * |
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661 | * @param callable $callback |
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662 | * @param bool $expected |
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663 | * |
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664 | * @return bool |
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665 | */ |
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666 | 1 | public function assert(callable $callback, $expected = true) |
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677 | |||
678 | /** |
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679 | * Pipe collection through a callback |
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680 | * |
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681 | * @param callable $callback |
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682 | * |
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683 | * @return mixed |
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684 | */ |
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685 | 1 | public function pipe(callable $callback) |
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689 | |||
690 | /** |
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691 | * Get new collection in chunks of $size |
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692 | * |
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693 | * Creates a new collection of arrays of $size length. The remainder items will be placed at the end. |
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694 | * |
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695 | * @param int $size |
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696 | * |
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697 | * @return Collection |
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698 | */ |
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699 | 2 | public function chunk($size) |
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703 | |||
704 | /** |
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705 | * Get a new collection of $count chunks |
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706 | * |
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707 | * @todo It might be useful to have a method that spreads remainder items more evenly so you don't end up with the |
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708 | * last item containing only one or two items. |
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709 | * |
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710 | * @param int $count |
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711 | * |
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712 | * @return Collection |
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713 | */ |
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714 | 1 | public function split($count = 1) |
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718 | |||
719 | /** |
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720 | * Get a slice of this collection. |
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721 | * |
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722 | * @param int $offset |
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723 | * @param int|null $length |
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724 | * |
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725 | * @return Collection |
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726 | */ |
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727 | 1 | public function slice($offset, $length = null) |
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731 | |||
732 | /** |
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733 | * Get collection with only differing items |
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734 | * |
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735 | * @param array|Traversable $items |
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736 | * |
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737 | * @return Collection |
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738 | */ |
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739 | 1 | public function diff($items) |
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743 | |||
744 | /** |
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745 | * Get collection with only differing items (by key) |
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746 | * |
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747 | * @param array|Traversable $items |
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748 | * |
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749 | * @return Collection |
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750 | */ |
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751 | 1 | public function kdiff($items) |
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755 | |||
756 | /** |
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757 | * Get collection with only intersecting items |
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758 | * |
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759 | * @param array|Traversable $items |
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760 | * |
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761 | * @return Collection |
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762 | */ |
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763 | 1 | public function intersect($items) |
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767 | |||
768 | /** |
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769 | * Get collection with only intersecting items (by key) |
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770 | * |
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771 | * @param array|Traversable $items |
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772 | * |
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773 | * @return Collection |
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774 | */ |
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775 | 1 | public function kintersect($items) |
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779 | |||
780 | /** |
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781 | * Remove last item in collection and return it |
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782 | * |
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783 | * @return mixed |
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784 | */ |
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785 | 1 | public function pop() |
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789 | |||
790 | /** |
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791 | * Remove first item in collection and return it (and re-index if numerically indexed) |
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792 | * |
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793 | * @return mixed |
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794 | */ |
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795 | 2 | public function shift() |
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799 | |||
800 | /** |
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801 | * Add item to the end of the collection |
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802 | * |
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803 | * @note This method is no different than add() but I included it for consistency's sake since I have the others |
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804 | * |
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805 | * @param mixed $item |
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806 | * |
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807 | * @return $this |
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808 | */ |
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809 | 1 | public function push($item) |
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813 | |||
814 | /** |
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815 | * Add item to the beginning of the collection (and re-index if a numerically indexed collection) |
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816 | * |
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817 | * @param mixed $item |
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818 | * |
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819 | * @return $this |
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820 | */ |
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821 | 2 | public function unshift($item) |
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827 | |||
828 | /** ++++ ++++ **/ |
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829 | /** ++ Interface Compliance ++ **/ |
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830 | /** ++++ ++++ **/ |
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831 | |||
832 | /** |
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833 | * @return array |
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834 | */ |
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835 | 1 | public function jsonSerialize() |
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839 | |||
840 | /** ++++ ++++ **/ |
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841 | /** ++ Array Access Methods ++ **/ |
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842 | /** ++++ ++++ **/ |
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843 | |||
844 | /** |
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845 | * {@inheritDoc} |
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846 | */ |
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847 | 1 | public function offsetExists($offset) |
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851 | |||
852 | /** |
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853 | * {@inheritDoc} |
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854 | */ |
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855 | 2 | public function offsetGet($offset) |
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863 | |||
864 | /** |
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865 | * {@inheritDoc} |
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866 | */ |
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867 | 1 | public function offsetUnset($offset) |
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871 | |||
872 | /** |
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873 | * {@inheritDoc} |
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874 | */ |
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875 | 1 | public function offsetSet($offset, $value) |
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883 | |||
884 | /** ++++ ++++ **/ |
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885 | /** ++ Iterator Methods ++ **/ |
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886 | /** ++++ ++++ **/ |
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887 | |||
888 | /** |
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889 | * {@inheritDoc} |
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890 | */ |
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891 | 30 | public function current() |
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895 | |||
896 | /** |
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897 | * {@inheritDoc} |
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898 | */ |
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899 | 30 | public function key() |
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903 | |||
904 | /** |
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905 | * {@inheritDoc} |
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906 | */ |
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907 | 29 | public function next() |
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911 | |||
912 | /** |
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913 | * {@inheritDoc} |
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914 | * |
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915 | * @todo Should this return $this? |
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916 | */ |
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917 | 83 | public function rewind() |
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921 | |||
922 | /** |
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923 | * {@inheritDoc} |
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924 | */ |
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925 | 30 | public function valid() |
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929 | |||
930 | /** ++++ ++++ **/ |
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931 | /** ++ Countable Method ++ **/ |
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932 | /** ++++ ++++ **/ |
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933 | |||
934 | /** |
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935 | * {@inheritDoc} |
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936 | */ |
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937 | 7 | public function count() |
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941 | } |