I have a string that I would like to format the same way I would a numeric value.
Ex:
int num = 2;
string option = num.ToString("000");
Console.WriteLine(option);
//output
//002
But the only way I can think to format it is to parse it as an int, then apply the ToString("000") method to it.
string option = "2";
option = int.Parse(option).ToString("000");
Is there a better, more direct way to do this?
No, there is no built-in mechanism to "format" a string as if it were a number. Some options:
Use string functions (Pad, Length, Substring) to determine what characters should be added
Parse to a numeric type and use ToString with numeric formatting strings
Use a reqular expression to extract the digits and generate a new string
There's not one "right" answer. Each has risks and benefits in terms of safety (what if the string does not represent a valid integer?), readability, performance, etc.
Would this suit your requirement?
string x = "2";
string formattedX = x.PadLeft(3, '0');
Console.WriteLine(formattedX); //prints 002
Related
I have looked around for this, but I'm not sure it's possible with string interpolation (I'm using VS2015).
string sequenceNumber = $"{fieldValuePrefix.ToUpper()}{separator}{similarPrefixes + 1:D4}";
Is there any way to make D4 a variable ? Some say yes, some no. Apparently, VS2015 C#6.0 is able to do it.
This works, it will return a string like WMT-0021, depending on fieldValuePrefix (WMT), separator (-) and the value of similarPrefixes (20). But I'd like the "D4" part to be a method argument instead of hardcoded in there.
Any ideas ?
You can, but you have to use explicit ToString call like this:
string format = "D4";
string sequenceNumber =
$"{fieldValuePrefix.ToUpper()}{separator}{(similarPrefixes + 1).ToString(format)}";
So I have this file with a number that I want to use.
This line is as follows:
TimeAcquired=1433293042
I only want to use the number part, but not the part that explains what it is.
So the output is:
1433293042
I just need the numbers.
Is there any way to do this?
Follow these steps:
read the complete line
split the line at the = character using string.Split()
extract second field of the string array
convert string to integer using int.Parse() or int.TryParse()
There is a very simple way to do this and that is to call Split() on the string and take the last part. Like so if you want to keep it as a string:
var myValue = theLineString.Split('=').Last();
If you need this as an integer:
int myValue = 0;
var numberPart = theLineString.Split('=').Last();
int.TryParse(numberPart, out myValue);
string setting=sr.ReadLine();
int start = setting.IndexOf('=');
setting = setting.Substring(start + 1, setting.Length - start);
A good approach to Extract Numbers Only anywhere they are found would be to:
var MyNumbers = "TimeAcquired=1433293042".Where(x=> char.IsDigit(x)).ToArray();
var NumberString = new String(MyNumbers);
This is good when the FORMAT of the string is not known. For instance you do not know how numbers have been separated from the letters.
you can do it using split() function as given below
string theLineString="your string";
string[] collection=theLineString.Split('=');
so your string gets divided in two parts,
i.e.
1) the part before "="
2) the part after "=".
so thus you can access the part by their index.
if you want to access numeric one then simply do this
string answer=collection[1];
try
string t = "TimeAcquired=1433293042";
t= t.replace("TimeAcquired=",String.empty);
After just parse.
int mrt= int.parse(t);
Here is my string
20.0e-6
I'm parsing it like
String Ans=Double.Parse("20.0e-6")
Now i'm getting the result like 2E-05
But the required output should be like
0.00002
How to get this?
The result of Double.Parse is a Double, not a string. You need to output a string from the double, using ToString.
You should also use an overload of Double.Parse that has a NumberStyles parameter. Using the Float value allows exponent notation:
string Ans=Double.Parse("20.0e-6", NumberStyles.Float).ToString("0.#####");
If you don't want to risk exceptions (InvlidCastException for example), you can use TryParse:
Double res;
if (Double.TryParse("20.0e-6", NumberStyles.Float,
CultureInfo.InvariantCulture ,res))
{
string Ans = res.ToString("0.#####");
}
It's the same number, but if you want to modify the output of the string, use a formatter on your ToString()
http://msdn.microsoft.com/en-us/library/dwhawy9k.aspx
So
String Ans=Double.Parse("20.0e-6").ToString("0.0####")
One way to get the result you want is to use String.Format as follow:
double x = 20.0e-6;
string y = string.Format("{0:0.######}",x);
Console.WriteLine(y);
Given your example, this outputs the value 0.00002
EDIT
I've just realised that this is actually the opposite of your question so in the aim of keeping the answer useful i'll add the following:
Given a string, you can parse as double and then apply the same logic as above. Probably not the most elegant solution however it offers another way to get the result you want.
string x = "20.0e-6";
var y = double.Parse(p);
Console.WriteLine(String.Format("{0:0.######}",y));
I have a coded string that I'd like to retrieve a value from. I realize that I can do some string manipulation (IndexOf, LastIndexOf, etc.) to pull out 12_35_55_219 from the below string but I was wondering if there was a cleaner way of doing so.
"AddedProject[12_35_55_219]0"
If you can be sure of the format of the string, then several possibilities exist:
My favorite is to create a very simple tokenizer:
string[] arrParts = yourString.Split( "[]".ToCharArray() );
Since there is a regular format to the string, arrParts will have three entries, and the part you're interested in would be arrParts[1].
If the string format varies, then you will have to use other techniques.
So in summary, if you have a pattern that you can apply to your string, the easiest is to use regular expressions, as per Guffa example.
On the other hand you have different tokens all the time to define the start and end of your string, then you should use the IndexOf and LastIndexOf combination and pass the tokens as a parameter, making the example from Fredrik a bit more generic:
string GetMiddleString(string input, string firsttoken, string lasttoken)
{
int pos1 = input.IndexOf(firsttoken) + 1;
int pos2 = input.IndexOf(lasttoken);
string result = input.Substring(pos1 , pos2 - pos1);
return result
}
And this is assuming that your tokens only happens one time in the string.
That depends on how much the string can vary. You can for example use a regular expression:
string input = "AddedProject[12_35_55_219]0";
string part = Regex.Match(input, #"\[[\d_]+\]").Captures[0].Value;
There are two methods which you may find useful, there is IndexOf and LastIndexOf with the square brackets as your parameters. With a little bit of research, you should be able to pull out the project number.
Here is a improvement from Wagner Silveira's GetMiddleString
string GetMiddleString(string input, string firsttoken, string lasttoken)
{
int pos1 = input.ToLower().IndexOf(firsttoken.ToLower()) + firsttoken.Length;
int pos2 = input.ToLower().IndexOf(lasttoken.ToLower());
return input.Substring(pos1 , pos2 - pos1);
}
And here how you use it
string data = "AddedProject[12_35_55_219]0";
string[] split = data.Split("[]".ToCharArray());
rtbHelp.Text += GetMiddleString(data, split[0], split[2]).Trim("[]".ToCharArray());//print it to my C# winForm RichTextBox Help
I have to deal with a numeric value (coming from a SQL Server 2005 numeric column) which I need to convert to a string, with the caveat that the decimal point has to be removed. The data itself is accessible in C# via a DataTable/DataRow.
For example, if the SQL Server column reads 12345.678, the string should be "12345678" when all is said and done. Would it be possible to point me toward a good approach for this? Maybe there's a .Net conversion method that does this, I'm not sure.
Thanks!
There are several possible approaches. You could convert it to a string using a specific culture so that you are sure that the period is used as decimal separator, then remove the period:
string s = num.ToString(CultureInfo.InvariantCulture).Replace(".", String.Empty);
You could use a more numeric approach to multiply the valye by 10 until there are no decimals:
while (num != Math.Floor(num)) num *= 10.0;
string s = ((int)num).ToString();
what about something like
var numberWithPoint = dbGetNumber();
string numberWithOutPoint = numberWithPoint.ToString().Replace(".", string.Empty);
it's quick and dirty, but it get the job done fairly simply.
you can do it in c# like:
var myNum = 12345.678;
var myString = myNum.ToString().Replace(".","");
in sql server, you can do it like:
SELECT REPLACE( cast(myCol as varchar), '.', '') as FormattedNumber
FROM ...
What about:
// using System.Globalization;
SqlCommand cm = new SqlCommand("SELECT 12345.678 as decimal");
// ...
SqlDataReader dr = cm.ExecuteReader();
if(dr.Read())
{
string value = dr.GetValue(0).ToString()
.Replace(NumberFormatInfo.CurrentInfo.NumberDecimalSeparator, "")
}
but usually when it comes from sql server, you should not convert it first to a string than to integer / double but convert it directly from object in row["column1"] to needed value, this will save you troubles handling cultures and improve performance a bit
A straightforward method is to use
string result = original.Replace(".", "")
There might be a faster method, but if this isn't in a tight inner loop, Replace should work fine.
EDIT: Fixed code example, plus:
To address culture concerns, one might use NumberFormatInfo.NumberDecimalSeparator to determine the currently defined decimal separator.
string result = Regex.Replace(original, "[^0-9]", "");