数组操作类_PHP教程

<span class</span><span  ArrayHelper{
    
    </span><span /*</span><span *
     * 从数组中删除空白的元素（包括只有空白字符的元素）
     *
     * 用法：
     * @code php
     * $arr = array('', 'test', '   ');
     * ArrayHelper::removeEmpty($arr);
     *
     * dump($arr);
     *   // 输出结果中将只有 'test'
     * @endcode
     *
     * @param array $arr 要处理的数组
     * @param boolean $trim 是否对数组元素调用 trim 函数
     </span><span */</span>
    <span static</span> <span function</span> removeEmpty(& <span $arr</span>, <span $trim</span> = <span TRUE</span><span )
    {
        </span><span foreach</span> (<span $arr</span> <span as</span> <span $key</span> => <span $value</span><span )
        {
            </span><span if</span> (<span is_array</span>(<span $value</span><span ))
            {
                self</span>::removeEmpty(<span $arr</span>[<span $key</span><span ]);
            }
            </span><span else</span><span 
            {
                </span><span $value</span> = <span trim</span>(<span $value</span><span );
                </span><span if</span> (<span $value</span> == ''<span )
                {
                    </span><span unset</span>(<span $arr</span>[<span $key</span><span ]);
                }
                </span><span elseif</span> (<span $trim</span><span )
                {
                    </span><span $arr</span>[<span $key</span>] = <span $value</span><span ;
                }
            }
        }
    }
    
    </span><span /*</span><span *
     * 从一个二维数组中返回指定键的所有值
     *
     * 用法：
     * @code php
     * $rows = array(
     *     array('id' => 1, 'value' => '1-1'),
     *     array('id' => 2, 'value' => '2-1'),
     * );
     * $values = ArrayHelper::getCols($rows, 'value');
     *
     * dump($values);
     *   // 输出结果为
     *   // array(
     *   //   '1-1',
     *   //   '2-1',
     *   // )
     * @endcode
     *
     * @param array $arr 数据源
     * @param string $col 要查询的键
     *
     * @return array 包含指定键所有值的数组
     </span><span */</span>
    <span static</span> <span function</span> getCols(<span $arr</span>, <span $col</span><span )
    {
        </span><span $ret</span> = <span array</span><span ();
        </span><span foreach</span> (<span $arr</span> <span as</span> <span $row</span><span )
        {
            </span><span if</span> (<span isset</span>(<span $row</span>[<span $col</span><span ])) {
                </span><span $ret</span>[] = <span $row</span>[<span $col</span><span ];
            }
        }
        </span><span return</span> <span $ret</span><span ;
    }
    
    </span><span /*</span><span *
     * 将一个二维数组转换为 HashMap，并返回结果
     *
     * 用法1：
     * @code php
     * $rows = array(
     *     array('id' => 1, 'value' => '1-1'),
     *     array('id' => 2, 'value' => '2-1'),
     * );
     * $hashmap = ArrayHelper::toHashmap($rows, 'id', 'value');
     *
     * dump($hashmap);
     *   // 输出结果为
     *   // array(
     *   //   1 => '1-1',
     *   //   2 => '2-1',
     *   // )
     * @endcode
     *
     * 如果省略 $valueField 参数，则转换结果每一项为包含该项所有数据的数组。
     *
     * 用法2：
     * @code php
     * $rows = array(
     *     array('id' => 1, 'value' => '1-1'),
     *     array('id' => 2, 'value' => '2-1'),
     * );
     * $hashmap = ArrayHelper::toHashmap($rows, 'id');
     *
     * dump($hashmap);
     *   // 输出结果为
     *   // array(
     *   //   1 => array('id' => 1, 'value' => '1-1'),
     *   //   2 => array('id' => 2, 'value' => '2-1'),
     *   // )
     * @endcode
     *
     * @param array $arr 数据源
     * @param string $keyField 按照什么键的值进行转换
     * @param string $valueField 对应的键值
     *
     * @return array 转换后的 HashMap 样式数组
     </span><span */</span>
    <span static</span> <span function</span> toHashmap(<span $arr</span>, <span $keyField</span>, <span $valueField</span> = <span NULL</span><span )
    {
        </span><span $ret</span> = <span array</span><span ();
        </span><span if</span> (<span $valueField</span><span )
        {
            </span><span foreach</span> (<span $arr</span> <span as</span> <span $row</span><span )
            {
                </span><span $ret</span>[<span $row</span>[<span $keyField</span>]] = <span $row</span>[<span $valueField</span><span ];
            }
        }
        </span><span else</span><span 
        {
            </span><span foreach</span> (<span $arr</span> <span as</span> <span $row</span><span )
            {
                </span><span $ret</span>[<span $row</span>[<span $keyField</span>]] = <span $row</span><span ;
            }
        }
        </span><span return</span> <span $ret</span><span ;
    }
    
    </span><span /*</span><span *
     * 将一个二维数组按照指定字段的值分组
     *
     * 用法：
     * @code php
     * $rows = array(
     *     array('id' => 1, 'value' => '1-1', 'parent' => 1),
     *     array('id' => 2, 'value' => '2-1', 'parent' => 1),
     *     array('id' => 3, 'value' => '3-1', 'parent' => 1),
     *     array('id' => 4, 'value' => '4-1', 'parent' => 2),
     *     array('id' => 5, 'value' => '5-1', 'parent' => 2),
     *     array('id' => 6, 'value' => '6-1', 'parent' => 3),
     * );
     * $values = ArrayHelper::groupBy($rows, 'parent');
     *
     * dump($values);
     *   // 按照 parent 分组的输出结果为
     *   // array(
     *   //   1 => array(
     *   //        array('id' => 1, 'value' => '1-1', 'parent' => 1),
     *   //        array('id' => 2, 'value' => '2-1', 'parent' => 1),
     *   //        array('id' => 3, 'value' => '3-1', 'parent' => 1),
     *   //   ),
     *   //   2 => array(
     *   //        array('id' => 4, 'value' => '4-1', 'parent' => 2),
     *   //        array('id' => 5, 'value' => '5-1', 'parent' => 2),
     *   //   ),
     *   //   3 => array(
     *   //        array('id' => 6, 'value' => '6-1', 'parent' => 3),
     *   //   ),
     *   // )
     * @endcode
     *
     * @param array $arr 数据源
     * @param string $keyField 作为分组依据的键名
     *
     * @return array 分组后的结果
     </span><span */</span>
    <span static</span> <span function</span> groupBy(<span $arr</span>, <span $keyField</span><span )
    {
        </span><span $ret</span> = <span array</span><span ();
        </span><span foreach</span> (<span $arr</span> <span as</span> <span $row</span><span )
        {
            </span><span $key</span> = <span $row</span>[<span $keyField</span><span ];
            </span><span $ret</span>[<span $key</span>][] = <span $row</span><span ;
        }
        </span><span return</span> <span $ret</span><span ;
    }
    
    </span><span /*</span><span *
     * 将一个平面的二维数组按照指定的字段转换为树状结构
     *
     * 用法：
     * @code php
     * $rows = array(
     *     array('id' => 1, 'value' => '1-1', 'parent' => 0),
     *     array('id' => 2, 'value' => '2-1', 'parent' => 0),
     *     array('id' => 3, 'value' => '3-1', 'parent' => 0),
     *
     *     array('id' => 7, 'value' => '2-1-1', 'parent' => 2),
     *     array('id' => 8, 'value' => '2-1-2', 'parent' => 2),
     *     array('id' => 9, 'value' => '3-1-1', 'parent' => 3),
     *     array('id' => 10, 'value' => '3-1-1-1', 'parent' => 9),
     * );
     *
     * $tree = ArrayHelper::tree($rows, 'id', 'parent', 'nodes');
     *
     * dump($tree);
     *   // 输出结果为：
     *   // array(
     *   //   array('id' => 1, ..., 'nodes' => array()),
     *   //   array('id' => 2, ..., 'nodes' => array(
     *   //        array(..., 'parent' => 2, 'nodes' => array()),
     *   //        array(..., 'parent' => 2, 'nodes' => array()),
     *   //   ),
     *   //   array('id' => 3, ..., 'nodes' => array(
     *   //        array('id' => 9, ..., 'parent' => 3, 'nodes' => array(
     *   //             array(..., , 'parent' => 9, 'nodes' => array(),
     *   //        ),
     *   //   ),
     *   // )
     * @endcode
     *
     * 如果要获得任意节点为根的子树，可以使用 $refs 参数：
     * @code php
     * $refs = null;
     * $tree = ArrayHelper::tree($rows, 'id', 'parent', 'nodes', $refs);
     *
     * // 输出 id 为 3 的节点及其所有子节点
     * $id = 3;
     * dump($refs[$id]);
     * @endcode
     *
     * @param array $arr 数据源
     * @param string $keyNodeId 节点ID字段名
     * @param string $keyParentId 节点父ID字段名
     * @param string $keyChildrens 保存子节点的字段名
     * @param boolean $refs 是否在返回结果中包含节点引用
     *
     * return array 树形结构的数组
     </span><span */</span>
    <span static</span> <span function</span> toTree(<span $arr</span>, <span $keyNodeId</span>, <span $keyParentId</span> = 'parent_id', <span $keyChildrens</span> = 'childrens', & <span $refs</span> = <span NULL</span><span )
    {
        </span><span $refs</span> = <span array</span><span ();
        </span><span foreach</span> (<span $arr</span> <span as</span> <span $offset</span> => <span $row</span><span )
        {
            </span><span $arr</span>[<span $offset</span>][<span $keyChildrens</span>] = <span array</span><span ();
            </span><span $refs</span>[<span $row</span>[<span $keyNodeId</span>]] =& <span $arr</span>[<span $offset</span><span ];
        }
    
        </span><span $tree</span> = <span array</span><span ();
        </span><span foreach</span> (<span $arr</span> <span as</span> <span $offset</span> => <span $row</span><span )
        {
            </span><span $parentId</span> = <span $row</span>[<span $keyParentId</span><span ];
            </span><span if</span> (<span $parentId</span><span )
            {
                </span><span if</span> (!<span isset</span>(<span $refs</span>[<span $parentId</span><span ]))
                {
                    </span><span $tree</span>[] =& <span $arr</span>[<span $offset</span><span ];
                    </span><span continue</span><span ;
                }
                </span><span $parent</span> =& <span $refs</span>[<span $parentId</span><span ];
                </span><span $parent</span>[<span $keyChildrens</span>][] =& <span $arr</span>[<span $offset</span><span ];
            }
            </span><span else</span><span 
            {
                </span><span $tree</span>[] =& <span $arr</span>[<span $offset</span><span ];
            }
        }
        </span><span return</span> <span $tree</span><span ;
    }
    
    </span><span /*</span><span *
     * 将树形数组展开为平面的数组
     *
     * 这个方法是 tree() 方法的逆向操作。
     *
     * @param array $tree 树形数组
     * @param string $keyChildrens 包含子节点的键名
     *
     * @return array 展开后的数组
     </span><span */</span>
    <span static</span> <span function</span> treeToArray(<span $tree</span>, <span $keyChildrens</span> = 'childrens'<span )
    {
        </span><span $ret</span> = <span array</span><span ();
        </span><span if</span> (<span isset</span>(<span $tree</span>[<span $keyChildrens</span>]) && <span is_array</span>(<span $tree</span>[<span $keyChildrens</span><span ]))
        {
            </span><span foreach</span> (<span $tree</span>[<span $keyChildrens</span>] <span as</span> <span $child</span><span )
            {
                </span><span $ret</span> = <span array_merge</span>(<span $ret</span>, self::treeToArray(<span $child</span>, <span $keyChildrens</span><span ));
            }
            </span><span unset</span>(<span $node</span>[<span $keyChildrens</span><span ]);
            </span><span $ret</span>[] = <span $tree</span><span ;
        }
        </span><span else</span><span 
        {
            </span><span $ret</span>[] = <span $tree</span><span ;
        }
        </span><span return</span> <span $ret</span><span ;
    }
    
    </span><span /*</span><span *
     * 根据指定的键对数组排序
     *
     * 用法：
     * @code php
     * $rows = array(
     *     array('id' => 1, 'value' => '1-1', 'parent' => 1),
     *     array('id' => 2, 'value' => '2-1', 'parent' => 1),
     *     array('id' => 3, 'value' => '3-1', 'parent' => 1),
     *     array('id' => 4, 'value' => '4-1', 'parent' => 2),
     *     array('id' => 5, 'value' => '5-1', 'parent' => 2),
     *     array('id' => 6, 'value' => '6-1', 'parent' => 3),
     * );
     *
     * $rows = ArrayHelper::sortByCol($rows, 'id', SORT_DESC);
     * dump($rows);
     * // 输出结果为：
     * // array(
     * //   array('id' => 6, 'value' => '6-1', 'parent' => 3),
     * //   array('id' => 5, 'value' => '5-1', 'parent' => 2),
     * //   array('id' => 4, 'value' => '4-1', 'parent' => 2),
     * //   array('id' => 3, 'value' => '3-1', 'parent' => 1),
     * //   array('id' => 2, 'value' => '2-1', 'parent' => 1),
     * //   array('id' => 1, 'value' => '1-1', 'parent' => 1),
     * // )
     * @endcode
     *
     * @param array $array 要排序的数组
     * @param string $keyname 排序的键
     * @param int $dir 排序方向
     *
     * @return array 排序后的数组
     </span><span */</span>
    <span static</span> <span function</span> sortByCol(<span $array</span>, <span $keyname</span>, <span $dir</span> =<span  SORT_ASC)
    {
        </span><span return</span> self::sortByMultiCols(<span $array</span>, <span array</span>(<span $keyname</span> => <span $dir</span><span ));
    }
    
    </span><span /*</span><span *
     * 将一个二维数组按照多个列进行排序，类似 SQL 语句中的 ORDER BY
     *
     * 用法：
     * @code php
     * $rows = ArrayHelper::sortByMultiCols($rows, array(
     *     'parent' => SORT_ASC,
     *     'name' => SORT_DESC,
     * ));
     * @endcode
     *
     * @param array $rowset 要排序的数组
     * @param array $args 排序的键
     *
     * @return array 排序后的数组
     </span><span */</span>
    <span static</span> <span function</span> sortByMultiCols(<span $rowset</span>, <span $args</span><span )
    {
        </span><span $sortArray</span> = <span array</span><span ();
        </span><span $sortRule</span> = ''<span ;
        </span><span foreach</span> (<span $args</span> <span as</span> <span $sortField</span> => <span $sortDir</span><span )
        {
            </span><span foreach</span> (<span $rowset</span> <span as</span> <span $offset</span> => <span $row</span><span )
            {
                </span><span $sortArray</span>[<span $sortField</span>][<span $offset</span>] = <span $row</span>[<span $sortField</span><span ];
            }
            </span><span $sortRule</span> .= '$sortArray[\'' . <span $sortField</span> . '\'], ' . <span $sortDir</span> . ', '<span ;
        }
        </span><span if</span> (<span empty</span>(<span $sortArray</span>) || <span empty</span>(<span $sortRule</span><span )) {
            </span><span return</span> <span $rowset</span><span ;
        }
        </span><span eval</span>('array_multisort(' . <span $sortRule</span> . '$rowset);'<span );
        </span><span return</span> <span $rowset</span><span ;
    }
    
    
}</span>

 

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