我从Facebook返回一个json对象,其中包含一些好友信息。
一些用户包含了他们的生日,一些用户没有,而另一些用户只包含了月份和日期。
我想对数组进行排序,将生日与当前日期接近的用户放在第一位。
我该怎么做?
json对象是这样的:
json = { "data" : [{name : "Joe Sam", id : "5555555", birthday: "02/02/1989" }, {name : "Joe Sam", id : 5555555, birthday: }, {name : "Joe Sam", id : 5555555, birthday: "01/01" }
您的JSON无效-如果这是实际的JSON字符串关键字需要引号。省略了结束的]和},中间记录的生日必须有某种值,例如,空字符串或null -或者根本不提供该键。我假设您可以解决这个问题,并且已经将JSON解析为一个名为json
的变量。
你也没有说日期是DD/MM(/YYYY)格式还是MM/DD(/YYYY)格式,所以我将编码为DD/MM,但你可以注释掉,使用MM/DD。
"最接近当前日期"有歧义:昨天比下周更接近吗?我就假定昨天是你所能得到的离现在最远的日期了。
这就是你的对象和一个排序例程。我还没有测试它,但即使假设它坏了,它也应该给你一个大致的想法:
var json = { "data" : [
{name : "Joe Sam", id : "5555555", birthday: "02/02/1989" },
{name : "Joe Sam", id : 5555555, birthday: null },
{name : "Joe Sam", id : 5555555, birthday: "01/01" }
]
};
// First sort into ascending birthday order, with people who didn't provide
// a birthday at the beginning of the list
function dayMonthComparer(a,b)
// note double-equals null also allows for undefined "birthday" property
if (aBD == null)
return bBD == null ? 0 : -1;
if (bBD == null)
return 1;
// next two lines allow for DD/MM format; comment them out for MM/DD format
aBD = aBD.substr(3,2) + aBD.substr(0,2);
bBD = bBD.substr(3,2) + bBD.substr(0,2);
// note: simple string compare works once in MM/DD format
return aBD === bBD ? 0 : (aBD > bBD ? 1 : -1);
}
json["data"].sort(function(a,b) {
return dayMonthComparer(a["birthday"],b["birthday"]);
});
// Next, find the first item in the array after the current date and
// move everything before that item to the end of the array.
var today = new Date(),
d = today.getDate(),
m = today.getMonth() + 1,
current,
firstNonBlank = null,
firstFromCurrent = 0;
if (d < 10) d = "0" + d;
if (m < 10) d = "0" + d;
current = d + "/" m;
// or use current = m + "/" + d if using American format
// get index of first item with birthday on or after current date
while(firstFromCurrent < json["data"].length &&
dayMonthComparer(current,json["data"][firstFromCurrent]["birthday"]) > 1) {
if (firstNonBlank===null &&
json["data"][firstFromCurrent]["birthday"] != null)
firstNonBlank = firstFromCurrent;
firstFromCurrent++;
}
if (firstFromCurrent < json["data"].length) {
json["data"] = json["data"].slice(firstFromCurrent)
.concat(json["data"].slice(firstNonBlank,firstFromCurrent),
json["data"].slice(0,firstNonBlank) );
}
// array is now sorted by birthday starting from current date, where
// those who didn't provide a birthday are at the end
.sort()
的工作原理请参考MDN文档