从对象数组构造一个元素数组? [英] Construct an array of elements from an array of objects?
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问题描述
有一个数据结构如下:
项目:[
{
标题: '一',
值:1,
},
{
标题:'Two',
值:2,
}
]
如何从项目中构建一个数组的标题?如['One','Two']
如果标题 == [] { ..
app.get('/',function(req,res){
var titles = [] ;
for(var i = 0,length = Items.length; i< length; i ++){
if titles == [] {
titles + = Items [i] ['标题'];
}
else {
titles = titles +','+ Items [i] ['title'];
}
console.log标题);
};
res.render('items',{
itemTitles:titles
});
});
解决方案
我只需使用 Array .map
返回新数组中的标题
var titles = Items.map(function o){
return o.title;
});
此外,错误是由于缺少括号
如果titles == [] {...
应该是
if(titles == []){...
/ pre>
甚至更好
if(Array.isArray标题)&& titles.length === 0){...
With a data structure that looks like this:
Items : [ { title : 'One', value : 1, }, { title : 'Two', value : 2, } ]
How would I construct an array of the titles from Items? As in ['One', 'Two']
This codeset generates a 'SyntaxError: Unexpected identifier' if titles == [] {..
app.get('/', function(req, res){ var titles = []; for (var i=0, length=Items.length; i < length; i++) { if titles == [] { titles += Items[i]['title']; } else { titles = titles + ', ' + Items[i]['title']; } console.log(titles); }; res.render('items', { itemTitles: titles }); });
解决方案I would just use
Array.map
to return the titles in a new arrayvar titles = Items.map(function(o) { return o.title; });
Also, the error is due to missing parentheses
if titles == [] { ...
should be
if (titles == []) { ...
or even better
if (Array.isArray(titles) && titles.length === 0) { ...
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