Develop Reference

Reformatting a string number value to use minus sign instead of parentheses for negative numbers

I built a service to read csv files of trade data from my new prime broker. The files show this format for negative numbers.
This is the code to read the file and process (only showing the part where I check for duplicate symbols since I am storing in Azure Table and cannot have duplicate symbols since the symbol is the row key)
for (var i = 0; i < records.Count - 1; i++)
{
//check if symbol is a duplicate
if (i>0 && records[i].Symbol == records[i - 1].Symbol)
{ //sum the columns in records[i] and records[i-1]
//change ent for symbol to new values
entities[i - (1 + dupeRecords)].CommissionPl = Convert.ToDouble(records[i].CommissionPl) + Convert.ToDouble(records[i - 1].CommissionPl).ToString(CultureInfo.InvariantCulture);
entities[i - (1 + dupeRecords)].PositionPl = Convert.ToDouble(records[i].PositionPl) + Convert.ToDouble(records[i - 1].PositionPl).ToString(CultureInfo.InvariantCulture);
entities[i - (1 + dupeRecords)].TransactionPl = Convert.ToDouble(records[i].TransactionPl) + Convert.ToDouble(records[i - 1].TransactionPl).ToString(CultureInfo.InvariantCulture);
entities[i - (1 + dupeRecords)].TotalPl = Convert.ToDouble(records[i].TotalPl) + Convert.ToDouble(records[i - 1].TotalPl).ToString(CultureInfo.InvariantCulture);
// do not create new ent for this record
//count the dupe entries for the entities index to match up
dupeRecords++;
}
The problem lies in the fact that these entries (i.e. records[i - 1].TotalPl, et al) when negative, despite showing -100 (for example) in the file show as (100) when you hover over them during processing. The Convert.ToDouble function can't process them when they are in parentheses format.
I can't figure out an EASY way to reformat the string value while iterating the records. I could check for parentheses and then strip them and multiply by -1 but I'm probably not seeing an easier solution.

Instead of using Convert.ToDouble, use double.Parse and specify the formats you allow:
NumberStyles styles = NumberStyles.AllowParentheses | NumberStyles.AllowTrailingSign | NumberStyles.Float | NumberStyles.AllowThousands;
entities[i - (1 + dupeRecords)].CommissionPl = double.Parse(records[i].CommissionPl, styles) ...

using OfficeOpenXml - Print cell.Value as Number

I am having some Cell values printed as Taxt (String) and i want them to be printed as Number, as this values are used in a Sum Formula.
The values came from an operation that i do with a library (OSISoft AF SDK) and are printed in my Excel as Strings.
ExcelRange cell = excelSheet.Cells[startRow, startCol + i + y];
cell.Value = valueAsString;
Just in case someone is using AF SDK as me getting data from PI Systems my code is actually something like this...
//point is a PIPoint.
cell.Value = point.RecordedValue(startDate.LocalTime.AddHours(i), OSIsoft.AF.Data.AFRetrievalMode.AtOrBefore);

Just parsing the value to double (or int) will be okey.
cell.Value = Double.Parse(cell.Value.ToString());
You can also set a Format to the number, but it is not necessary:
cell.Style.Numberformat.Format = "0.00";
All formats available:
https://stackoverflow.com/a/40214134/6574873

Format text by adding whitespace

I am trying to format strings by whitespaces.
All strings normally look like
01. Anton 30p
02. Cinderella 20p
03. Thomas 18p
04. Anastacia-Laura 16p
I want to format each string, that the points start at the same column.
There I wrote:
s = stringUpToName;
int addSpacing = 37 - s.Length;
for (int i = 0; i < addSpacing; i += 1) s += " ";
s += points;
It gets closer this way, but it's still not perfectly formatted.
I want it to look like this:
01. Anton 30p
02. Cinderella 20p
03. Thomas 18p
04. Anastacia-Laura 16p

Use "0" custom specifier as zero-placeholder symbol to format index/number of record. 0:00 will give you 01 for value 1.
Also keep in mind that item format syntax is { index[,alignment][:formatString]} where alignment indicates preferred formatted field width. So, adding alignment to second item format {1,20} gives you right-aligned field width of 20 characters. With negative alignment field will be left-aligned.
Total format string will look like "{0:00}. {1,-20}{2}p"
You can use it with String.Format or StringBuilder.AppendFormat if you are build string, or Console.WriteLine if you are writing it to console.
int index = 1;
string name = "Anton";
int points = 30;
var result = String.Format("{0:00}. {1,-20}{2}p", index, name, points)
// "01. Anton 30p"

String.Format and Composite Formatting using the Alignment functionality
string[] names = new string[]
{
"1. Anton 30p",
"2. Cinderella 20p",
"3. Thomas 18p",
"4. Anastacia-Laura 16p"
};
foreach(string s in names)
{
int lastSpace = s.LastIndexOf(' ');
int firstSpace = s.IndexOf(' ');
string result = string.Format("{0,-4}{1,-37}{2,4}", s.Substring(0, firstSpace), s.Substring(firstSpace + 1, lastSpace), s.Substring(lastSpace+1));
Console.WriteLine(result);
}
Keep in mind that to see the output exactly aligned in columns you need to use a Fixed Width font like Lucida Console or Courier, because fonts with variable width use less pixel to print an I than to print a W.

Try right-align the numbers using
String.Format("{0} {1} {2,4}p",
Num,
Name,
Point);

decimal ToString formatting which gives at least 1 digit, no upper limit

How to format a decimal in C# with at least one digit after the decimal point, but not a fixed upper limit if specified more than 1 digit after the decimal point:
5 -> "5.0"
5.1 -> "5.1"
5.122 -> "5.122"
10.235544545 -> "10.235544545"

Use ToString("0.0###########################").
Some notes:,
There are 27 #s in there, as the decimal structure can accommodate precision up to 28 decimal places.
The 0 custom specifier will cause a digit to always be displayed, even if the value is 0.
The # custom specifier only displays a value if the digit is zero and all of the digits to the right/left of that digit (depending on what side of the decimal point you are on) are zero.
You will need to insert as many # after the first 0 to the right of the decimal point to accommodate the length of all the values you will pass to ToString, if you will only have precision to 10 decimal places, then you need nine # (since you have the first decimal place to the right handled by 0)
For more information, see the section of MSDN titled "Custom Numeric Format Strings".

[TestClass]
public class UnitTest1
{
[TestMethod]
public void TestMethod1()
{
var a = 5m;
var b = 5.1m;
var c = 5.122m;
var d = 10.235544545m;
var ar = DecToStr.Work(a);
var br = DecToStr.Work(b);
var cr = DecToStr.Work(c);
var dr = DecToStr.Work(d);
Assert.AreEqual(ar, "5.0");
Assert.AreEqual(br, "5.1");
Assert.AreEqual(cr, "5.122");
Assert.AreEqual(dr, "10.235544545");
}
}
public class DecToStr
{
public static string Work(decimal val)
{
if (val * 10 % 10 == 0)
return val.ToString("0.0");
else
return val.ToString();
}
}

Func<decimal, string> FormatDecimal = d => (
d.ToString().Length <= 3 ||
!d.ToString().Contains(".")) ? d.ToString("#.0") : d.ToString()
);

Whats the best way to format this number?

I have a double and I want to format it with the following rules:
If there are no decimal places show just the number (see 100 example below)
If there are any decimal places show 2 decimal places
So, as a few examples:
100 --> 100
99.958443534 --> 99.96
99.1 -> 99.10

You could check if its a whole number, the use the type of formatting based on that:
string res = string.Format(((number % 1) == 0) ? "{0:0}" : "{0:0.00}", number);

What about:
var a = 100;
var b = 99.95844354;
var aAnswer = a.ToString("0.##"); //aAnswer is "100"
var bAnswer = b.ToString("0.##"); //bAnswer is "99.96"

You can use:
decimal a = 99.949999999M;
Math.Round(a, 2); // Returns 99.95