CsvHelper-将多列读入单个列表 [英] CsvHelper - read in multiple columns to a single list

问题描述

我正在使用 CSVHelper 读取大量数据

I'm using CSVHelper to read in lots of data

我想知道是否有可能读取其中的最后 n 列并将其转置为列表

I'm wondering if it's possible to read the last n columns in and transpose them to a list

"Name","LastName","Attribute1","Attribute2","Attribute3"

并将数据模制成这样的东西

And mould the data into something like this

public class Person
{
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public IList<string> Attributes { get; set; }
}

我想一步一步做到这一点，我敢肯定我可以有一个中间步骤，将一个具有匹配属性属性的对象放入其中，但是最好一次完成

I'm looking to do this in one step, I'm sure I could have an intermediate step where I put into an object with matching attribute properties but it would be nice to do it on a one-er

推荐答案

这可以作为映射器来解决。

This does the trick as a mapper.

public sealed class PersonMap : CsvClassMap<Person>
{
    private List<string> attributeColumns = 
        new List<string> { "Attribute1", "Attribute2", "Attribute3" };

    public override void CreateMap()
    {
        Map(m => m.FirstName).Name("FirstName").Index(0);
        Map(m => m.LastName).Name("LastName").Index(1);
        Map(m => m.Attributes).ConvertUsing(row =>
            attributeColumns
                .Select(column => row.GetField<string>(column))
                .Where(value => String.IsNullOrWhiteSpace(value) == false)
            );
    }
}

然后，您只需要这样的东西

Then you just need something like this

using (var reader = new CsvReader(new StreamReader(filePath)))
{
    reader.Configuration.RegisterClassMap<PersonMap>();
    while (reader.Read())
    {
        var card = reader.GetRecord<Person>();
    }
}

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