Develop Reference

How to put decimal point in a whole number

I'm reading a text file from bank with a string of numbers. 0000000010050, the amount of this string is $ 100.50, but is there a way to insert a decimal point in the string? here is my code.
string amount = 0000000010050;
string f_amount = "";
string ff_amount = "";
decimal d_amount = 0;
f_amount = amount.Trim();
d_amount = int.Parse(f_amount.TrimStart('0')); // this part removes the zeros and the output is 10050.
ff_amount = string.Format("{0:0,0.00}", d_amount); // this line outputs 10050.00
how to make the output looks like this 100.50?

First convert the string to decimal and apply string.Format in this way
string.Format("{0:#.00}", Convert.ToDecimal(bankString) / 100);
this will give the result 100.50
https://dotnetfiddle.net/WrRVFo

Something like this (let's take CultureInfo into account)
using System.Globalization;
...
string amount = "0000000010050";
amount = amount
.Insert(amount.Length - CultureInfo.CurrentCulture.NumberFormat.CurrencyDecimalDigits,
CultureInfo.CurrentCulture.NumberFormat.CurrencyDecimalSeparator)
.TrimStart('0');

Insert spaces into string using string.format

I've been using C# String.Format for formatting numbers before like this (in this example I simply want to insert a space):
String.Format("{0:### ###}", 123456);
output:
"123 456"
In this particular case, the number is a string. My first thought was to simply parse it to a number, but it makes no sense in the context, and there must be a prettier way.
Following does not work, as ## looks for numbers
String.Format("{0:### ###}", "123456");
output:
"123456"
What is the string equivalent to # when formatting? The awesomeness of String.Format is still fairly new to me.

You have to parse the string to a number first.
int number = int.Parse("123456");
String.Format("{0:### ###}", number);
of course you could also use string methods but that's not as reliable and less safe:
string strNumber = "123456";
String.Format("{0} {1}", strNumber.Remove(3), strNumber.Substring(3));

As Heinzi pointed out, you can not have format specifier for string arguments.
So, instead of String.Format, you may use following:
string myNum="123456";
myNum=myNum.Insert(3," ");

Not very beautiful, and the extra work might outweigh the gains, but if the input is a string on that format, you could do:
var str = "123456";
var result = String.Format("{0} {1}", str.Substring(0,3), str.Substring(3));

string is not a IFormattable
Console.WriteLine("123456" is IFormattable); // False
Console.WriteLine(21321 is IFormattable); // True
No point to supply a format if the argument is not IFormattable only way is to convert your string to int or long

We're doing string manipulation, so we could always use a regex.
Adapted slightly from here:
class MyClass
{
static void Main(string[] args)
{
string sInput, sRegex;
// The string to search.
sInput = "123456789";
// The regular expression.
sRegex = "[0-9][0-9][0-9]";
Regex r = new Regex(sRegex);
MyClass c = new MyClass();
// Assign the replace method to the MatchEvaluator delegate.
MatchEvaluator myEvaluator = new MatchEvaluator(c.ReplaceNums);
// Replace matched characters using the delegate method.
sInput = r.Replace(sInput, myEvaluator);
// Write out the modified string.
Console.WriteLine(sInput);
}
public string ReplaceNums(Match m)
// Replace each Regex match with match + " "
{
return m.ToString()+" ";
}
}
How's that?
It's been ages since I used C# and I can't test, but this may work as a one-liner which may be "neater" if you only need it once:
sInput = Regex("[0-9][0-9][0-9]").Replace(sInput,MatchEvaluator(Match m => m.ToString()+" "));

There is no way to do what you want unless you parse the string first.
Based on your comments, you only really need a simple formatting so you are better off just implementing a small helper method and thats it. (IMHO it's not really a good idea to parse the string if it isn't logically a number; you can't really be sure that in the future the input string might not be a number at all.
I'd go for something similar to:
public static string Group(this string s, int groupSize = 3, char groupSeparator = ' ')
{
var formattedIdentifierBuilder = new StringBuilder();
for (int i = 0; i < s.Length; i++)
{
if (i != 0 && (s.Length - i) % groupSize == 0)
{
formattedIdentifierBuilder.Append(groupSeparator);
}
formattedIdentifierBuilder.Append(s[i]);
}
return formattedIdentifierBuilder.ToString();
}
EDIT: Generalized to generic grouping size and group separator.

The problem is that # is a Digit placeholder and it is specific to numeric formatting only. Hence, you can't use this on strings.
Either parse the string to a numeric, so the formatting rules apply, or use other methods to split the string in two.
string.Format("{0:### ###}", int.Parse("123456"));

Convert string value to decimal with thousand separator?

This might be a very simple question.
Suppose text box show value 10,000.12 when user edits data by mistake he remove first two numbers like ,000.12 and using this textbox in the calculation then it gives an exception. I want a just validate text box.
For Example:
string str = ",100.12;"
Convert to
decimal number = 100.12;
Any Idea?.
It shows only whole number when user remove any thousand separator.

This is pretty messed up and I am not sure if all of you strings will look the same, but in case they do this might do the trick:
string str = ",0,100.12";
decimal number;
bool converted = decimal.TryParse(str.Substring(str.LastIndexOf(",") + 1), out number);
The variable converted will tell you whether or not your string was converted and you will not an exception.
Good luck!

If I understood the question, you want to remove all characters that would prevent the parse routine from failing.
string str = ",0,100.12";
var modified = new StringBuilder();
foreach (char c in str)
{
if (Char.IsDigit(c) || c == '.')
modified.Append(c);
}
decimal number= decimal.Parse(modified.ToString());

string a = "100.12";
decimal b = Convert.ToDecimal(a);

string str = ",0,100.12;";
var newstr = Regex.Replace(str,#"[^\d\.]+","");
decimal d = decimal.Parse(newstr, CultureInfo.InvariantCulture);

String Find & Replace Method

I need to locate a specific part of a string value like the one below, I need to alter the "Meeting ID" to a specific number.
This number comes from a dropdownlist of multiple numbers, so I cant simply use find & replace. As the text could change to one of multiple numbers before the user is happy.
The "0783," part of the string never changes, and "Meeting ID" is always followed by a ",".
So i need to get to "0783, INSERT TEXT ," and then insert the new number on the Index Changed event.
Here is an example :-
Business Invitation, start time, M Problem, 518-06-xxx, 9999 999
0783, Meeting ID, xxx ??
What is the best way of locating this string and replacing the test each time?
I hope this makes sense guys?

Okay, so there are several ways of doing this, however this seems to be a string you have control over so I'm going to say here's what you want to do.
var myString = string.Format("Business Invitation, start time, M Problem, 518-06-xxx, 9999 999 0783, {0}, xxx ??", yourMeetingId);
If you don't have control over it then you're going to have to be a bit more clever:
var startingIndex = myString.IndexOf("0783, ");
var endingIndex = myString.IndexOf(",", startingIndex + 6);
var pattern = myString.Substring(startingIndex + 6, endingIndex - (startingIndex + 6));
myString = myString.Replace(pattern, yourMeetingId);

You should store your "current" Meeting ID in a variable, changing it along with your user's actions, and then use that same global variable whenever you need the string.
This way, you don't have to worry about what's inside the string and don't need to mess with array indexes. You will also be safe from magic numbers / strings, which are bound to blow up in your face at some point in the future.

You can try with Regex.Replace method
string pattern = #"\d{3},";
Regex regex = new Regex(pattern);
var inputStr = "518-06-xxx, 9999 999 0783";
var replace = "..."
var outputStr = regex.Replace(inputStr, replace);

use Regex.Split by token "0783," then in the second string in the array return split by token "," the first element in the string array would be where you would insert new text. Then use string.Join to join the first split with "0783," and the join the second with ",".
string temp = "Business Invitation, start time, M Problem, 518-06-xxx, 9999 999 0783, Meeting ID, xxx ??";
string newID = "1234";
string[] firstSplits = Regex.Split(temp, "0783,");
string[] secondSplits = Regex.Split(firstSplits[1], ",");
secondSplits[0] = newID;
string #join = string.Join(",", secondSplits);
firstSplits[1] = #join;
string newString = string.Join("0783,", firstSplits);

Remove formatting from a string: "(123) 456-7890" => "1234567890"?

I have a string when a telephone number is inputted - there is a mask so it always looks like "(123) 456-7890" - I'd like to take the formatting out before saving it to the DB.
How can I do that?

One possibility using linq is:
string justDigits = new string(s.Where(c => char.IsDigit(c)).ToArray());
Adding the cleaner/shorter version thanks to craigmoliver
string justDigits = new string(s.Where(char.IsDigit).ToArray())

You can use a regular expression to remove all non-digit characters:
string phoneNumber = "(123) 456-7890";
phoneNumber = Regex.Replace(phoneNumber, #"[^\d]", "");
Then further on - depending on your requirements - you can either store the number as a string or as an integer. To convert the number to an integer type you will have the following options:
// throws if phoneNumber is null or cannot be parsed
long number = Int64.Parse(phoneNumber, NumberStyles.Integer, CultureInfo.InvariantCulture);
// same as Int64.Parse, but returns 0 if phoneNumber is null
number = Convert.ToInt64(phoneNumber);
// does not throw, but returns true on success
if (Int64.TryParse(phoneNumber, NumberStyles.Integer,
CultureInfo.InvariantCulture, out number))
{
// parse was successful
}

Since nobody did a for loop.
long GetPhoneNumber(string PhoneNumberText)
{
// Returns 0 on error
StringBuilder TempPhoneNumber = new StringBuilder(PhoneNumberText.Length);
for (int i=0;i<PhoneNumberText.Length;i++)
{
if (!char.IsDigit(PhoneNumberText[i]))
continue;
TempPhoneNumber.Append(PhoneNumberText[i]);
}
PhoneNumberText = TempPhoneNumber.ToString();
if (PhoneNumberText.Length == 0)
return 0;// No point trying to parse nothing
long PhoneNumber = 0;
if(!long.TryParse(PhoneNumberText,out PhoneNumber))
return 0; // Failed to parse string
return PhoneNumber;
}
used like this:
long phoneNumber = GetPhoneNumber("(123) 456-7890");
Update
As pr commented many countries do have zero's in the begining of the number, if you need to support that, then you have to return a string not a long. To change my code to do that do the following:
1) Change function return type from long to string.
2) Make the function return null instead of 0 on error
3) On successfull parse make it return PhoneNumberText

You can make it work for that number with the addition of a simple regex replacement, but I'd look out for higher initial digits. For example, (876) 543-2019 will overflow an integer variable.

string digits = Regex.Replace(formatted, #"\D", String.Empty, RegexOptions.Compiled);

Aside from all of the other correct answers, storing phone numbers as integers or otherwise stripping out formatting might be a bad idea.
Here are a couple considerations:
Users may provide international phone numbers that don't fit your expectations. See these examples So the usual groupings for standard US numbers wouldn't fit.
Users may NEED to provide an extension, eg (555) 555-5555 ext#343 The # key is actually on the dialer/phone, but can't be encoded in an integer. Users may also need to supply the * key.
Some devices allow you to insert pauses (usually with the character P), which may be necessary for extensions or menu systems, or dialing into certain phone systems (eg, overseas). These also can't be encoded as integers.
[EDIT]
It might be a good idea to store both an integer version and a string version in the database. Also, when storing strings, you could reduce all punctuation to whitespace using one of the methods noted above. A regular expression for this might be:
// (222) 222-2222 ext# 333 -> 222 222 2222 # 333
phoneString = Regex.Replace(phoneString, #"[^\d#*P]", " ");
// (222) 222-2222 ext# 333 -> 2222222222333 (information lost)
phoneNumber = Regex.Replace(phoneString, #"[^\d]", "");
// you could try to avoid losing "ext" strings as in (222) 222-2222 ext.333 thus:
phoneString = Regex.Replace(phoneString, #"ex\w+", "#");
phoneString = Regex.Replace(phoneString, #"[^\d#*P]", " ");

Try this:
string s = "(123) 456-7890";
UInt64 i = UInt64.Parse(
s.Replace("(","")
.Replace(")","")
.Replace(" ","")
.Replace("-",""));
You should be safe with this since the input is masked.

You could use a regular expression or you could loop over each character and use char.IsNumber function.

You would be better off using regular expressions. An int by definition is just a number, but you desire the formatting characters to make it a phone number, which is a string.
There are numerous posts about phone number validation, see A comprehensive regex for phone number validation for starters.

As many answers already mention, you need to strip out the non-digit characters first before trying to parse the number. You can do this using a regular expression.
Regex.Replace("(123) 456-7890", #"\D", String.Empty) // "1234567890"
However, note that the largest positive value int can hold is 2,147,483,647 so any number with an area code greater than 214 would cause an overflow. You're better off using long in this situation.
Leading zeros won't be a problem for North American numbers, as area codes cannot start with a zero or a one.

Alternative using Linq:
string phoneNumber = "(403) 259-7898";
var phoneStr = new string(phoneNumber.Where(i=> i >= 48 && i <= 57).ToArray());

This is basically a special case of C#: Removing common invalid characters from a string: improve this algorithm. Where your formatng incl. White space are treated as "bad characters"

'you can use module / inside sub main form VB.net
Public Function ClearFormat(ByVal Strinput As String) As String
Dim hasil As String
Dim Hrf As Char
For i = 0 To Strinput.Length - 1
Hrf = Strinput.Substring(i, 1)
If IsNumeric(Hrf) Then
hasil &= Hrf
End If
Next
Return Strinput
End Function
'you can call this function like this
' Phone= ClearFormat(Phone)

public static string DigitsOnly(this string phoneNumber)
{
return new string(
new[]
{
// phoneNumber[0], (
phoneNumber[1], // 6
phoneNumber[2], // 1
phoneNumber[3], // 7
// phoneNumber[4], )
// phoneNumber[5],
phoneNumber[6], // 8
phoneNumber[7], // 6
phoneNumber[8], // 7
// phoneNumber[9], -
phoneNumber[10], // 5
phoneNumber[11], // 3
phoneNumber[12], // 0
phoneNumber[13] // 9
});
}