目的: 1> jQuery.map : 產生一個新的陣列，但只包含原陣列的特定欄位
2>jQuery.grep: 產生一個新的陣列，但只包含合乎條件的項目
Ex: var people =[
{name: 'Apple' , sex: 'female'},
{name: 'Bob' , sex: 'male'},
{name: 'Jacky' , sex: 'male'},
{name: 'Oliver' , sex: 'male'},
{name: 'Apple' , sex: 'female'},
{name: 'Bob' , sex: 'male'},
{name: 'Jacky' , sex: 'male'},
{name: 'Oliver' , sex: 'male'},
{name: 'Helen' , sex: 'female'},
]
處理說明: 1>取得 people 的 name 陣列
var nameList = $.map(people, function(item, index) { return item.name;
});
--> 結果: [ 'Apple', 'Bob', 'Helen', 'Jacky', 'Oliver']
--> 結果: [ 'Apple', 'Bob', 'Helen', 'Jacky', 'Oliver']
2>取得people 中為女姓的 陣列
var femaleList = $.grep(people, function(item, index) { return item.sex === 'female'; });
--> 結果: [{name: 'Apple' , sex: 'female'},
var femaleList = $.grep(people, function(item, index) { return item.sex === 'female'; });
--> 結果: [{name: 'Apple' , sex: 'female'},
{name: 'Helen' , sex: 'female'},
]
傳統寫法:
1>取得 people 的 name 陣列
var nameList=[];
$.each(people,function(index,item){
nameList.push(people.name);
}
-->
var nameList=$.map(people,function(item,index){ return item.name; });
2>取得 people 中為 femail 的人員陣列
var femaleList=[];
$.each(people,function(index,item){
if (item.sex=='female)
femaleList.push(item);
}
-->
var femaleList=$.grep(people,function(item,index){
if (item.sex=='female'){
return item; }
});
