Javascript 遍历对象哈希表
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Iterating through an object hashtable
提问by Nyxynyx
I am trying to use a hashtable so I can select a specific object stored in an array/object. However, I am having a problem looping through an object.
我正在尝试使用哈希表，以便我可以选择存储在数组/对象中的特定对象。但是，我在遍历对象时遇到问题。
var pins= {};
pins[6] = '6';
pins[7] = '7';
pins[8] = '8';
$('#result3').append('<div>Size: ' + Object.size(pins) + '</div>');
for(var i = 0; i < Object.size(pins); i++) {
$('#result3').append('<div>' + pins[i] + '</div>');
}
JSFiddle: http://jsfiddle.net/7TrSU/
JSFiddle：http: //jsfiddle.net/7TrSU/
As you can see in TEST 3which uses object pinto store the data, I am getting undefinedwhen looping through the object pin.
正如您所看到的，TEST 3其中使用 objectpin来存储数据，我undefined在遍历 object时得到了pin。
What is the correct way for looping through pin?
循环的正确方法是pin什么？
EDIT
编辑
What happens if instead of just pin[6] = '6', I make pin[6] = an object and I want to loop through the all their idproperties? Actual code snippet of what I'm doing...
如果pin[6] = '6'我使 pin[6] = 一个对象而不是仅仅，并且我想遍历它们的所有id属性，会发生什么情况？我正在做的实际代码片段...
for(var i = 0; i < json.length; i++) {
markerId = json[i].listing_id
// Place markers on map
var latLng = new google.maps.LatLng(json[i].lat, json[i].lng);
var marker = new google.maps.Marker({
listing_id: markerId,
position: latLng,
icon: base_url + 'images/template/markers/listing.png',
});
markers[markerId] = marker;
}
for(var marker in markers) {
console.log('marker ID: ' + marker.listing_id);
mc.addMarker(marker);
}
The console.logabove returns undefined, and if I do console.log(marker)instead, I get the value of marker.listing_id. Sorry I'm getting confused!
将console.log上述收益不确定，如果我这样做console.log(marker)，而不是，我得到的价值marker.listing_id。对不起，我开始糊涂了！
I managed to get it to work with $.each(markers, function(i, marker){});but why does the for..inabove not work?
我设法让它工作，$.each(markers, function(i, marker){});但为什么for..in上述不起作用？
回答by Raynos
var hash = {}
hash[key] = value
Object.keys(hash).forEach(function (key) {
var value = hash[key]
// iteration code
})
回答by Rob W
Don't use a for(i=0; i<size; i++)loop. Instead, use:
不要使用for(i=0; i<size; i++)循环。相反，使用：
Object.keys(pins)to get a list of properties, and loop through it, or- Use a
for ( key_name in pins)in conjunction withObject.hasOwnProperty(to exclude inherit properties) to loop through the properties.
Object.keys(pins)获取属性列表，并循环遍历它，或- 将 a
for ( key_name in pins)与Object.hasOwnProperty（排除继承属性）结合使用以循环访问属性。
The problem of your third test case is that it reads the values of keys 0, 1 and 2 (instead of 6, 7, 8).
第三个测试用例的问题在于它读取键 0、1 和 2（而不是 6、7、8）的值。
回答by Quentin
Since you are using jQuery:
由于您使用的是 jQuery：
jQuery.each(pins, function (name, value) {
$('#result3').append('<div>' + name + "=" + value + '</div>');
});
回答by Rory McCrossan
Try this:
尝试这个：
for (var pin in pins) {
$('#result3').append('<div>' + pin + '</div>');
}
回答by pbfy0
function iterate(obj){
var keys = Object.keys(obj);
for(i in keys){
doSomething(obj[keys[i]].id);
}
}
This iterates over the idof all fields in any object
这将遍历id任何对象中的所有字段
回答by Wouter J
The pinbegins with 6 up to 8, but the for loop loops from 0 up to 3 (the length of the object). You need to loop from 6 up to 6 + the_size_of_the_object. Something like this:
的pin具有6到8开始，而是从0到3（该物体的长度）for循环环路。您需要从 6 循环到6 + the_size_of_the_object. 像这样的东西：
for(var i = 6, len = 6 + Object.size(pins); i < len; i++) {
$('#result3').append('<div>' + pins[i] + '</div>');
}
Or something like this, this is what I like:
或者像这样的东西，这就是我喜欢的：
for( var i = 5; pin = pins[++i]; ) {
$('#result3').append('<div>' + pin + '</div>');
}
