Question

我有一个json：

items = "[
{"prop1":"here","prop2":"all","contentType":"All","dateRangeType":"Anytime","prop3b":"here"},
{"prop1":"pole","prop2":"all","contentType":"All","dateRangeType":"Anytime","excludeWords":"there ","excludeDomains":"asteroid","prop3b":"pole"},
{"prop1":"orcsstar","prop2":"all","contentType":"All","dateRangeType":"Anytime","excludeWords":"","excludeDomains":"dwarves","prop3b":"orcsstar"},
{"prop1":"guntham","prop2":"all","contentType":"All","dateRangeType":"Anytime","excludeWords":"","prop3b":"gunther"},
{"prop1":"depot","prop2":"all","contentType":"All","dateRangeType":"Anytime","excludeWords":"","prop3b":"depot"},
{"prop1":"department","prop2":"all","contentType":"All","dateRangeType":"Anytime","excludeWords":"dept","prop3b":"depart"}
]"

所以我在这里有6个条目存储在var项目中。我如何才能获得4个条目。我尝试过切片，但它在“{}”括号上并没有很好地分开。或[]，在开始时出现，请帮助我选择{}。中包含的4个条目的子数组。

Answer 1

一旦你纠正外部引号

，切片就可以了

＆＃13;

items = '[{"prop1":"here","prop2":"all","contentType":"All","dateRangeType":"Anytime","prop3b":"here"},{"prop1":"pole","prop2":"all","contentType":"All","dateRangeType":"Anytime","excludeWords":"there","excludeDomains":"asteroid","prop3b":"pole"},{"prop1":"orcsstar","prop2":"all","contentType":"All","dateRangeType":"Anytime","excludeWords":"","excludeDomains":"dwarves","prop3b":"orcsstar"},{"prop1":"guntham","prop2":"all","contentType":"All","dateRangeType":"Anytime","excludeWords":"","prop3b":"gunther"},{"prop1":"depot","prop2":"all","contentType":"All","dateRangeType":"Anytime","excludeWords":"","prop3b":"depot"},{"prop1":"department","prop2":"all","contentType":"All","dateRangeType":"Anytime","excludeWords":"dept","prop3b":"depart"}]'


var parsedAndSlicedAndStringified = JSON.stringify(JSON.parse(items).slice(0,4), null, 4);

document.getElementById('pre').innerHTML = parsedAndSlicedAndStringified ;;

＆＃13;

<pre id="pre">

＆＃13;

Answer 2

这应该保留为对象JSON.parse(items)而不是字符串，并使用像Underscore这样的库在对象中搜索您想要的项目，或只是.slice(0,3)来获取第一个4.如果需要返回字符串JSON.stringify()上面的结果。

完整JS中的前4项：

JSON.stringify(JSON.parse(items).slice(0,3))

从json的一部分中提取少数病例

2 个答案: