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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26 | class Collection implements ArrayAccess, Iterator, Countable, JsonSerializable |
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27 | { |
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28 | /** @var array */ |
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29 | protected $items; |
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30 | |||
31 | /** |
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32 | * Collection constructor. |
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33 | * |
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34 | * @param array $items |
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35 | */ |
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36 | 90 | public function __construct(array $items = []) |
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41 | |||
42 | /** |
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43 | * Generate a collection from an array of items. |
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44 | * I created this method so that it's possible to extend a collection more easily. |
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45 | * |
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46 | * @param array $items |
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47 | * |
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48 | * @todo call to_array on $items and don't require input to be an array. |
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49 | * |
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50 | * @return Collection |
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51 | */ |
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52 | 29 | public static function factory(array $items = []) |
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56 | |||
57 | /** |
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58 | * Get collection as an array |
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59 | * |
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60 | * @return array |
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61 | */ |
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62 | 46 | public function toArray() |
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66 | |||
67 | /** |
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68 | * Determine if collection has a given key |
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69 | * |
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70 | * @param mixed $key The key to look for |
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71 | * |
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72 | * @return bool |
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73 | */ |
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74 | 45 | public function has($key) |
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78 | |||
79 | /** |
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80 | * Does collection have item at position? |
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81 | * |
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82 | * Determine if collection has an item at a particular position (indexed from one). |
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83 | * Position can be positive and start from the beginning or it can be negative and |
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84 | * start from the end. |
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85 | * |
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86 | * @param int $position |
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87 | * |
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88 | * @return bool |
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89 | */ |
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90 | 2 | public function hasValueAt($position) |
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99 | |||
100 | /** |
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101 | * Get key at given position |
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102 | * |
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103 | * Returns the key at the given position, starting from one. Position can be positive (start from beginning) or |
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104 | * negative (start from the end). |
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105 | * |
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106 | * If the position does not exist, a RuntimeException is thrown. |
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107 | * |
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108 | * @param int $position |
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109 | * |
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110 | * @return string |
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111 | * |
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112 | * @throws RuntimeException |
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113 | */ |
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114 | 6 | public function getKeyAt($position) |
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128 | |||
129 | /** |
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130 | * Get value at given position |
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131 | * |
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132 | * Returns the value at the given position, starting from one. Position can be positive (start from beginning) or |
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133 | * negative (start from the end). |
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134 | * |
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135 | * If the position does not exist, a RuntimeException is thrown. |
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136 | * |
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137 | * @param int $position |
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138 | * |
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139 | * @return mixed |
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140 | * |
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141 | * @throws RuntimeException |
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142 | */ |
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143 | 2 | public function getValueAt($position) |
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147 | |||
148 | /** |
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149 | * Get the key of the first item found matching $item |
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150 | * |
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151 | * @todo Perhaps this should allow a callback in place of $item? |
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152 | * |
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153 | * @param mixed $item |
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154 | * |
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155 | * @return mixed|null |
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156 | */ |
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157 | 1 | public function keyOf($item) |
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167 | |||
168 | /** |
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169 | * Get the offset (index) of the first item found that matches $item |
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170 | * |
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171 | * @todo Perhaps this should allow a callback in place of $item? |
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172 | * |
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173 | * @param mixed $item |
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174 | * |
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175 | * @return int|null |
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176 | */ |
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177 | 1 | public function indexOf($item) |
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189 | |||
190 | /** |
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191 | * Get item by key, with an optional default return value |
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192 | * |
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193 | * @param mixed $key |
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194 | * @param mixed $default |
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195 | * |
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196 | * @return mixed |
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197 | */ |
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198 | 8 | public function get($key, $default = null) |
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206 | |||
207 | /** |
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208 | * Add an item with no regard to key |
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209 | * |
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210 | * @param mixed $value |
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211 | * |
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212 | * @return $this |
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213 | */ |
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214 | 8 | public function add($value) |
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220 | |||
221 | /** |
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222 | * Set an item at a given key |
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223 | * |
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224 | * @param mixed $key |
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225 | * @param mixed $value |
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226 | * @param bool $overwrite If false, do not overwrite existing key |
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227 | * |
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228 | * @return $this |
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229 | */ |
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230 | 14 | public function set($key, $value, $overwrite = true) |
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238 | |||
239 | /** |
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240 | * Delete an item by key |
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241 | * |
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242 | * @param mixed $key |
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243 | * |
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244 | * @return $this |
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245 | */ |
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246 | 3 | public function delete($key) |
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252 | |||
253 | /** |
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254 | * Clear the collection of all its items. |
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255 | * |
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256 | * @return $this |
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257 | */ |
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258 | 2 | public function clear() |
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264 | |||
265 | /** |
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266 | * Determine if collection contains given value |
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267 | * |
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268 | * @param mixed|callable $val |
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269 | * @param mixed $key |
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270 | * |
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271 | * @return bool |
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272 | */ |
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273 | 4 | public function contains($val, $key = null) |
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291 | |||
292 | /** |
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293 | * Fetch item from collection by key and remove it from collection |
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294 | * |
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295 | * @param mixed $key |
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296 | * |
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297 | * @return mixed |
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298 | */ |
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299 | 1 | public function pull($key) |
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307 | |||
308 | /** |
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309 | * Join collection items using a delimiter |
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310 | * |
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311 | * @param string $delim |
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312 | * |
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313 | * @return string |
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314 | */ |
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315 | 1 | public function join($delim = '') |
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319 | |||
320 | /** |
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321 | * Determine if collection has any items |
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322 | * |
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323 | * @return bool |
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324 | */ |
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325 | 4 | public function isEmpty() |
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329 | |||
330 | /** |
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331 | * Get a collection of only this collection's values (without its keys) |
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332 | * |
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333 | * @return Collection |
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334 | */ |
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335 | 1 | public function values() |
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339 | |||
340 | /** |
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341 | * Get a collection of only this collection's keys |
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342 | * |
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343 | * @return Collection |
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344 | */ |
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345 | 1 | public function keys() |
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349 | |||
350 | /** |
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351 | * Get a collection with order reversed |
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352 | * |
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353 | * @return Collection |
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354 | */ |
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355 | 6 | public function reverse() |
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359 | |||
360 | /** |
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361 | * Get a collection with keys and values flipped |
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362 | * |
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363 | * @return Collection |
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364 | */ |
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365 | 1 | public function flip() |
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373 | |||
374 | /** |
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375 | * Shuffle the order of this collection's values |
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376 | * |
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377 | * @return Collection |
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378 | */ |
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379 | 1 | public function shuffle() |
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384 | |||
385 | /** |
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386 | * Get a random value from the collection |
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387 | * |
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388 | * @todo might be useful to add a $count param to specify you want $count random items... |
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389 | * |
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390 | * @return mixed |
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391 | */ |
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392 | 1 | public function random() |
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396 | |||
397 | /** |
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398 | * Sort the collection (using values) |
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399 | * |
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400 | * @param callable $alg |
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401 | * |
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402 | * @return $this |
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403 | */ |
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404 | 2 | public function sort(callable $alg = null) |
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414 | |||
415 | /** |
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416 | * Sort the collection (using keys) |
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417 | * |
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418 | * @param callable $alg |
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419 | * |
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420 | * @return $this |
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421 | */ |
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422 | 2 | public function ksort(callable $alg = null) |
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432 | |||
433 | /** |
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434 | * Append items to collection without regard to keys |
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435 | * |
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436 | * @param array|Traversable $items |
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437 | * |
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438 | * @return $this |
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439 | */ |
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440 | 2 | public function append($items) |
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452 | |||
453 | /** |
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454 | * Return first item or first item where callback returns true |
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455 | * |
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456 | * @param callable|null $callback |
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457 | * |
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458 | * @return mixed|null |
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459 | */ |
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460 | 7 | public function first(callable $callback = null) |
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471 | |||
472 | /** |
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473 | * Return last item or last item where callback returns true |
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474 | * |
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475 | * @param callable|null $callback |
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476 | * |
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477 | * @return mixed|null |
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478 | */ |
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479 | 3 | public function last(callable $callback = null) |
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483 | |||
484 | /** |
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485 | * Map collection |
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486 | * |
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487 | * Create a new collection using the results of a callback function on each item in this collection. |
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488 | * |
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489 | * @param callable $callback |
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490 | * |
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491 | * @return Collection |
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492 | */ |
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493 | 3 | public function map(callable $callback) |
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504 | |||
505 | /** |
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506 | * Combine collection with another traversable/collection |
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507 | * |
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508 | * Using this collection's keys, and the incoming collection's values, a new collection is created and returned. |
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509 | * |
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510 | * @param array|Traversable $items |
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511 | * |
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512 | * @return Collection |
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513 | */ |
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514 | 5 | public function combine($items) |
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527 | |||
528 | /** |
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529 | * Get a new collection with only distinct values |
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530 | * |
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531 | * @return Collection |
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532 | */ |
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533 | 1 | public function distinct() |
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544 | |||
545 | /** |
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546 | * Remove all duplicate values from collection in-place |
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547 | * |
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548 | * @return Collection |
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549 | */ |
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550 | 1 | public function deduplicate() |
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556 | |||
557 | /** |
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558 | * Return a new collection with only filtered keys/values |
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559 | * |
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560 | * The callback accepts value, key, index and should return true if the item should be added to the returned |
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561 | * collection |
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562 | * |
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563 | * @param callable $callback |
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564 | * |
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565 | * @return Collection |
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566 | */ |
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567 | 2 | public function filter(callable $callback = null) |
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585 | |||
586 | /** |
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587 | * Fold collection into a single value |
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588 | * |
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589 | * Loop through collection calling a callback function and passing the result to the next iteration, eventually |
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590 | * returning a single value. |
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591 | * |
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592 | * @param callable $callback |
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593 | * @param mixed $initial |
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594 | * |
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595 | * @return null |
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596 | */ |
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597 | 1 | public function fold(callable $callback, $initial = null) |
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607 | |||
608 | /** |
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609 | * Return a merge of this collection and $items |
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610 | * |
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611 | * @param array|Traversable $items |
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612 | * |
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613 | * @return Collection |
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614 | */ |
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615 | 3 | public function merge($items) |
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628 | |||
629 | /** |
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630 | * Create a new collection with a union of this collection and $items |
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631 | * |
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632 | * This method is similar to merge, except that existing items will not be overwritten. |
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633 | * |
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634 | * @param $items |
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635 | */ |
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636 | 2 | public function union($items) |
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649 | |||
650 | /** |
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651 | * Call callback for each item in collection, passively |
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652 | * If at any point the callback returns false, iteration stops. |
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653 | * |
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654 | * @param callable $callback |
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655 | * |
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656 | * @return $this |
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657 | */ |
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658 | 2 | public function each(callable $callback) |
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669 | |||
670 | /** |
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671 | * Assert callback returns $expected value for each item in collection. |
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672 | * |
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673 | * @todo This can be used to easily make methods like all($callback) and none($callback). |
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674 | * |
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675 | * @param callable $callback |
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676 | * @param bool $expected |
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677 | * |
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678 | * @return bool |
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679 | */ |
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680 | 1 | public function assert(callable $callback, $expected = true) |
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691 | |||
692 | /** |
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693 | * Pipe collection through a callback |
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694 | * |
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695 | * @param callable $callback |
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696 | * |
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697 | * @return mixed |
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698 | */ |
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699 | 1 | public function pipe(callable $callback) |
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703 | |||
704 | /** |
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705 | * Get new collection in chunks of $size |
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706 | * |
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707 | * Creates a new collection of arrays of $size length. The remainder items will be placed at the end. |
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708 | * |
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709 | * @param int $size |
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710 | * |
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711 | * @return Collection |
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712 | */ |
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713 | 2 | public function chunk($size) |
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717 | |||
718 | /** |
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719 | * Get a new collection of $count chunks |
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720 | * |
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721 | * @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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722 | * last item containing only one or two items. |
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723 | * |
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724 | * @param int $count |
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725 | * |
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726 | * @return Collection |
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727 | */ |
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728 | 1 | public function split($count = 1) |
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732 | |||
733 | /** |
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734 | * Get a slice of this collection. |
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735 | * |
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736 | * @param int $offset |
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737 | * @param int|null $length |
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738 | * |
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739 | * @return Collection |
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740 | */ |
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741 | 1 | public function slice($offset, $length = null) |
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745 | |||
746 | /** |
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747 | * Get collection with only differing items |
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748 | * |
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749 | * @param array|Traversable $items |
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750 | * |
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751 | * @return Collection |
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752 | */ |
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753 | 1 | public function diff($items) |
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757 | |||
758 | /** |
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759 | * Get collection with only differing items (by key) |
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760 | * |
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761 | * @param array|Traversable $items |
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762 | * |
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763 | * @return Collection |
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764 | */ |
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765 | 1 | public function kdiff($items) |
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769 | |||
770 | /** |
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771 | * Get collection with only intersecting items |
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772 | * |
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773 | * @param array|Traversable $items |
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774 | * |
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775 | * @return Collection |
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776 | */ |
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777 | 1 | public function intersect($items) |
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781 | |||
782 | /** |
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783 | * Get collection with only intersecting items (by key) |
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784 | * |
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785 | * @param array|Traversable $items |
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786 | * |
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787 | * @return Collection |
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788 | */ |
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789 | 1 | public function kintersect($items) |
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793 | |||
794 | /** |
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795 | * Remove last item in collection and return it |
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796 | * |
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797 | * @return mixed |
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798 | */ |
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799 | 1 | public function pop() |
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803 | |||
804 | /** |
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805 | * Remove first item in collection and return it (and re-index if numerically indexed) |
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806 | * |
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807 | * @return mixed |
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808 | */ |
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809 | 2 | public function shift() |
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813 | |||
814 | /** |
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815 | * Add item to the end of the collection |
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816 | * |
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817 | * @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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818 | * |
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819 | * @param mixed $item |
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820 | * |
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821 | * @return $this |
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822 | */ |
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823 | 1 | public function push($item) |
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827 | |||
828 | /** |
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829 | * Add item to the beginning of the collection (and re-index if a numerically indexed collection) |
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830 | * |
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831 | * @param mixed $item |
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832 | * |
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833 | * @return $this |
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834 | */ |
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835 | 5 | public function unshift($item) |
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841 | |||
842 | /** |
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843 | * Get new collection padded to specified $size with $value |
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844 | * |
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845 | * Using $value, pad the collection to specified $size. If $size is smaller or equal to the size of the collection, |
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846 | * then no padding takes place. If $size is positive, padding is added to the end, while if negative, padding will |
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847 | * be added to the beginning. |
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848 | * |
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849 | * @param int $size |
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850 | * @param mixed $value |
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851 | * |
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852 | * @return Collection |
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853 | */ |
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854 | 3 | public function pad($size, $value = null) |
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867 | |||
868 | /** |
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869 | * Partition collection into two collections using a callback |
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870 | * |
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871 | * Iterates over each element in the collection with a callback. Items where callback returns true are placed in one |
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872 | * collection and the rest in another. Finally, the two collections are placed in an array and returned for easy use |
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873 | * with the list() function. ( list($a, $b) = $col->partition(function($val, $key, $index) {}) ) |
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874 | * |
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875 | * @param callable $callback |
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876 | * |
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877 | * @return array<Collection> |
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878 | */ |
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879 | 2 | public function partition(callable $callback) |
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895 | |||
896 | /** ++++ ++++ **/ |
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897 | /** ++ Interface Compliance ++ **/ |
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898 | /** ++++ ++++ **/ |
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899 | |||
900 | /** |
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901 | * @return array |
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902 | */ |
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903 | 1 | public function jsonSerialize() |
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907 | |||
908 | /** ++++ ++++ **/ |
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909 | /** ++ Array Access Methods ++ **/ |
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910 | /** ++++ ++++ **/ |
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911 | |||
912 | /** |
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913 | * {@inheritDoc} |
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914 | */ |
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915 | 1 | public function offsetExists($offset) |
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919 | |||
920 | /** |
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921 | * {@inheritDoc} |
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922 | */ |
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923 | 2 | public function offsetGet($offset) |
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931 | |||
932 | /** |
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933 | * {@inheritDoc} |
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934 | */ |
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935 | 1 | public function offsetUnset($offset) |
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939 | |||
940 | /** |
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941 | * {@inheritDoc} |
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942 | */ |
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943 | 1 | public function offsetSet($offset, $value) |
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951 | |||
952 | /** ++++ ++++ **/ |
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953 | /** ++ Iterator Methods ++ **/ |
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954 | /** ++++ ++++ **/ |
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955 | |||
956 | /** |
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957 | * {@inheritDoc} |
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958 | */ |
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959 | 33 | public function current() |
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963 | |||
964 | /** |
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965 | * {@inheritDoc} |
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966 | */ |
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967 | 33 | public function key() |
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971 | |||
972 | /** |
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973 | * {@inheritDoc} |
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974 | */ |
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975 | 32 | public function next() |
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979 | |||
980 | /** |
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981 | * {@inheritDoc} |
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982 | * |
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983 | * @todo Should this return $this? |
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984 | */ |
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985 | 90 | public function rewind() |
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989 | |||
990 | /** |
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991 | * {@inheritDoc} |
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992 | */ |
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993 | 34 | public function valid() |
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997 | |||
998 | /** ++++ ++++ **/ |
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999 | /** ++ Countable Method ++ **/ |
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1000 | /** ++++ ++++ **/ |
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1001 | |||
1002 | /** |
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1003 | * {@inheritDoc} |
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1004 | */ |
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1005 | 10 | public function count() |
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1009 | } |