如何使用 CsvHelper 控制浮点数的格式

如何解决如何使用 CsvHelper 控制浮点数的格式

要在写日期时间时控制格式，可以这样做

var input = 'du';
var sl = ["dune","to kill a mockingbird","leaves of grass","the sun and her flowers","lord of the flies","the grapes of wrath"];

var slc = sl.filter(str => str.includes(input));

// to make unique
slc = slc.filter((str,i)=>i===slc.indexOf(str));

我希望类似地指定一个控制浮点数格式的图片字符串。我试过了。

var options = new CsvHelper.TypeConversion.TypeConverterOptions { 
  Formats = new[] { 
    "yyyy-MM-dd HH:mm" 
  } 
};

但它不起作用。

如何将格式字符串与var options = new CsvHelper.TypeConversion.TypeConverterOptions { Formats = new[] { "yyyy-MM-dd HH:mm","###.#" } }; 或float关联起来？

我需要将 format 强制转换为第二个示例 (double) 中显示的图片字符串，因为 FORTRAN 程序使用生成的 CSV 非常挑剔，不会在它期望的 "###.#" 处接受 "245"。

消费程序的源不可用。建议我修复它没有帮助。

解决方法

要强制添加 0 需要使用 zero placeholder：

public class Foo
{
    public int Id { get; set; }
    public string Name { get; set; }
    public DateTime Time { get; set; }
    public float Value1 { get; set; }
    public double Value2 { get; set; }
}

var records = new List<Foo>
{
    new Foo { Id = 1,Name = "one",Time = DateTime.Now,Value1 = 1.123f,Value2 = 12345.789 },new Foo { Id = 2,Name = "two",Value1 = 123f,Value2 = 44 },};

var dt_options = new CsvHelper.TypeConversion.TypeConverterOptions { 
    Formats = new[] {  "yyyy-MM-dd HH:mm" }  };
var float_options = new CsvHelper.TypeConversion.TypeConverterOptions { 
    Formats = new[] { "###.0" } };

using (var writer = new StreamWriter("file.csv"))
using (var csv = new CsvWriter(writer,CultureInfo.InvariantCulture))
{
    csv.Configuration.TypeConverterOptionsCache.AddOptions<DateTime>(dt_options);
    csv.Configuration.TypeConverterOptionsCache.AddOptions<float>(float_options);
    csv.Configuration.TypeConverterOptionsCache.AddOptions<double>(float_options);

    csv.WriteRecords(records);
}

Id,Name,Time,Value1,Value2
1,one,2021-01-07 20:54,1.1,12345.8
2,two,123.0,44.0

如果需要将所有值包装到引号中，请配置 CsvWriter：

..
using (var csv = new CsvWriter(writer,new CsvConfiguration(CultureInfo.InvariantCulture) { 
        ShouldQuote = (_,_) => true  }))
..

/*
"Id","Name","Time","Value1","Value2"
"1","one","2021-01-07 21:11","1.1","12345.8"
"2","two","123.0","44.0"
*/