使用Linq选择列表外的项

Question

使用Linq选择列表外的项

4

I have a list like

     {
        "Nutrients": [{
            "vitamin": "vitamin C",
            "potassium": "195mg",
            "sodium": "2mg",
            "cholesterol": "",
            "display_name": "Apple"
        }, {
            "vitamin": "vitamin B",
            "potassium": "176mg",
            "sodium": "2mg",
            "cholesterol": "",
            "display_name": "Grape"
        }],
        "General_name": "Fruits",
        "country_of_origin": "France"


     }


     {
        "Nutrients": [{
            "vitamin": "vitamin B",
            "potassium": "196mg",
            "sodium": "115mg",
            "cholesterol": "123mg",
            "display_name": "Chicken"

        }, {
            "vitamin": "vitamin B",
            "potassium": "360mg",
            "sodium": "53mg",
            "cholesterol": "68mg",
            "display_name": "Chicken"
        }],
        "General_name": "Meat",
        "country_of_origin": "Denmark"

     }

我需要找出那些胆固醇为空字符串的项目的通用名称。

我尝试使用LINQ Lambda表达式：

var elements=items.SelectMany(c =>c.Nutrients)
    .Where(a => !string.IsNullOrEmpty(a.cholesterol))
    .ToList();

我的问题是如何从这个条件中获取通用名称

- Mithun

1个回答

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- Igor · Accepted Answer

var elements = items.Where(x => x.Nutrients.Any(a => !string.IsNullOrEmpty(a.cholesterol)))
   .Select(x => x.GeneralName)
   .ToList();

这将为您提供一个包含胆固醇非空值的营养素集合的所有GeneralName值列表。这是您要寻找的吗？

编辑：

有没有办法也获取这些项目的display_name？

var elements = items.Where(x => x.Nutrients.Any(a => !string.IsNullOrEmpty(a.Cholesterol)))
    .Select(x => new {x.GeneralName, DisplayNames = x.Nutrients.Where(a => !string.IsNullOrEmpty(a.Cholesterol)).Select(y => y.DisplayName).ToList()})
    .ToList();