{
   object: XYZ,
   ts : new Date()
}

db.data.find({object : XYZ, ts : {$gt : t1, $lt : t2}})

// first
db.data.find({object : XYZ, ts : {$gt : new Date(/* start of day */)}}).sort({ts : 1}).limit(1)
// last
db.data.find({object : XYZ, ts : {$lt : new Date(/* end of day */)}}).sort({ts : -1}).limit(1)

db.data.find({ts : timestamp})

// Parse a n delimited file into RAM then
// then split each line on space to into a
// array of tokens.  Return the entire array
// as string[][]
let readSpaceDelimFile fname =
    System.IO.File.ReadAllLines(fname)
    |> Array.map (fun line -> line.Split [|' '|])

// Based on a two dimensional array
// pull out a single column for bar
// close and convert every value
// for every row to a float
// and return the array of floats.
let GetArrClose(tarr : string[][])  =
    [| for aLine in tarr do
         //printfn "aLine=%A" aLine
         let closep = float(aLine.[5])
         yield closep
    |]