[ { "categoryId": "1850", "parentId": "1847" }, { "categoryId": "1852", "parentId": "1847" }, { "categoryId": "1854", "parentId": "1847" }, { "categoryId": "1893", "parentId": "1889" }, { "categoryId": "1896", "parentId": "1889" }, { "categoryId": "1907", "parentId": "1902" }, { "categoryId": "1909", "parentId": "1902" }]想找到相同的parentId，去除重复，只保留一个，categoryId则是相同parentId的合集，具体效果是这样的：[ { "parentId": "1847", "categoryId": ["1850","1852","1854"], }, { "parentId": "1889" "categoryId": ["1893","1896"], }, { "parentId": "1902" "categoryId": ["1907","1909"], }]