我经常使用CSV类型提供程序,它将元组用于所有底层数据。我的问题是,我遇到有很多列的csv文件,并发现围绕操作这种大小的数据构建基础设施相当麻烦。如何构建一个只更新特定列子集的函数,而不必创建庞大的模式匹配语句?请参阅下面的代码示例。
// I want to generate lots of sample data for the first three columns
// And I would like to avoid creating giant record types in order to
// do this task as the csv's are always changing and the records would
// have to change as well
type CumbersomeCSVRow = // 17 fields now, but imagine 212
string * string * string * Option<int> * string *
Option<int> * string * string * string * string *
string * string * Option<float> * string *
Option<float> * Option<float> * string
// Here is a sample row of data
let sampleCumbersomeRow : CumbersomeCSVRow =
("First","Second","Third",Some(52),"MSCI",None,"B74A123","",
"Airlines","Transportation","","",Some(1.04293),"Updated",
Some(0.95),Some(56.7423),"Measured")
// Record type of the sample data that I want to 'insert' into the cumbersome data type
type FirstThreeStrings =
{ First : string; Second : string; Third : string}
// and some instances of the new data
let generatedFrontMatters =
// imagine lots of sample data and workflows to create it, hence the records
seq { for letter in ["A";"B";"C"] ->
{ First = letter;
Second = letter + letter
Third = letter + letter + letter } }
https://stackoverflow.com/questions/50614975
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