根據值重新排列JSON的一部分

Question

我有以下JSON，如果類型是'水果'或'肉'，我想根據'等級'進行重新排列。並保持JSON的其餘部分的顯示順序。 「水果」和「肉類」類型將具有排名，但類型「蔬菜」和「日記」排名不是強制性的，在某些情況下可能沒有。

原值：

var results = {"docs":[ 
    {"type":"fruit","name":"apple","rank": 10}, 
    {"type":"vegetable","name":"carrot","rank": 0}, 
    {"type":"fruit","name":"grape","rank": 9}, 
    {"type":"meat","name":"beef","rank": 9}, 
    {"type":"meat","name":"fish","rank": 10.1}, 
    {"type":"vegetable","name":"tamato"}, 
    {"type":"meat","name":"chicken","rank": 10}, 
    {"type":"diary","name":"eggs"}, 
    {"type":"vegetable","name":"peas","rank": 0}, 
    {"type":"fruit","name":"orange","rank": 9.1}, 
    {"type":"diary","name":"milk","rank": 10}, 
    {"type":"fruit","name":"banana","rank": 9.8} 
]}; 

期望值：

var results = {"docs":[ 
    {"type":"fruit","name":"apple","rank": 10}, 
    {"type":"fruit","name":"banana","rank": 9.8}, 
    {"type":"fruit","name":"orange","rank": 9.1}, 
    {"type":"fruit","name":"grape","rank": 9}, 
    {"type":"meat","name":"fish","rank": 10.1}, 
    {"type":"meat","name":"chicken","rank": 10}, 
    {"type":"meat","name":"beef","rank": 9}, 
    {"type":"vegetable","name":"carrot","rank": 0}, 
    {"type":"vegetable","name":"tamato"}, 
    {"type":"diary","name":"eggs"}, 
    {"type":"vegetable","name":"peas","rank": 0}, 
    {"type":"diary","name":"milk","rank": 10} 
]}; 

在此先感謝。感謝幫助。

Answer 1

您的JSON對象的docs元素是一個JSON對象數組，因此您可以使用Array.sort（）方法對JSON對象進行排序（請參閱：https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/sort）。訣竅是編寫一個排序函數，按您希望排序的方式排序您的JSON對象。

我這樣做是通過將其分解爲兩個函數，一個按類型排序，另一個按排名排序。

按類型排序時，我們希望將水果分類到比肉類低的指數，而乳製品和蔬菜分類到比水果或肉類低的指數。我們可以在compareType中使用類型數組的索引來幫助我們按類型進行排序。 「果實」的指數大於「肉」的指數，而不在數組中的任何指標（「乳製品」和「蔬菜」）的指數爲-1。類型數組中較低的索引對應於最終排序數組中較高的索引。因此，如果a.type < b.type，我們返回1.

當按排名排序時，應將較高排名排序爲較低排名索引。最後的排序函數首先比較對象的類型，如果類型相同，則比較它們的排名。

var results = {"docs":[ 
    {"type":"fruit","name":"apple","rank": 10}, 
    {"type":"vegetable","name":"carrot","rank": 0}, 
    {"type":"fruit","name":"grape","rank": 9}, 
    {"type":"meat","name":"beef","rank": 9}, 
    {"type":"meat","name":"fish","rank": 10.1}, 
    {"type":"vegetable","name":"tamato"}, 
    {"type":"meat","name":"chicken","rank": 10}, 
    {"type":"diary","name":"eggs"}, 
    {"type":"vegetable","name":"peas","rank": 0}, 
    {"type":"fruit","name":"orange","rank": 9.1}, 
    {"type":"diary","name":"milk","rank": 10}, 
    {"type":"fruit","name":"banana","rank": 9.8} 
]}; 

function compareRank(a, b) { 
    if(a.rank < b.rank) { 
    return 1; 
    } 
    else if(a.rank > b.rank) { 
    return -1; 
    } 
    else { 
    return 0; 
    } 
} 

function compareType(a, b) { 
    var types = ["meat", "fruit"]; 

    if(a.type === b.type) { 
    return 0; 
    } 
    else if(types.indexOf(a.type) < types.indexOf(b.type)) { 
    return 1; 
    } 
    else { 
    return -1; 
    } 
} 

var docs = results.docs; 
docs.sort(function(a, b) { 
    if(compareType(a, b) === 0) { 
    return compareRank(a, b); 
    } 
    else { 
    return compareType(a, b); 
    } 
});