String.Format() split integer value - c#

I'm wondering if it's possible for .Net's String.Format() to split an integer apart into two sub strings. For example I have a number 3234 and I want to format it as 32X34. My integer will always have 4 or 6 digits. Is this possible using String.Format()? If so what format string would work?
P.S.
I know there is other ways to do this, but i'm specifically interested to know if String.Format() can handle this.

You can specify your own format when calling String.Format
String.Format("{0:00x00}", 2398) // = "23x93"

James, I'm not sure you've completely specified the problem. If your goal is to put the 'x' in the center of the string, Samuel's answer won't work for 6 digit numbers. String.Format("{0:00x00}", 239851) returns "2398x51" instead of "239x851"
Instead, try:
String.Format(val<10000 ? "{0:00x00}" : "{0:000x000}", val)
In either case, the method is called Composite Formatting.
(I'm assuming the numbers will be between 1000 and 999999 inclusive. Even then, numbers between 1000 and 1009 inclusive will report the number after the 'x' with an unnecessary leading '0'. So maybe this approach is valid for values between 1010 and 999999 inclusive.)

No, it can't.
In fact, it seems that your integers aren't integers. Perhaps they should be stored in a class, with its own ToString() method that will format them this way.

Related

how to add zeros for integer variable

I'm very new to c# programming. I want to know how to add leading zeros for a integer type in c#.
ex:
int value = 23;
I want to use it like this ;
0023
Thanks in advance
You can't. There's no such contextual information in an int. An integer is just an integer.
If you're talking about formatting, you could use something like:
string formatted = value.ToString("0000");
... that will ensure there are at least 4 digits. (A format string of "D4" will have the same effect.) But you need to be very clear in your mind that this is only relevant in the string representation... it's not part of the integer value represented by value. Similarly, value has no notion of whether it's in decimal or hex - again, that's a property of how you format it.
(It's really important to understand this in reasonably simple cases like this, as it tends to make a lot more difference for things like date/time values, which again don't store any formatting information, and people often get confused.)
Note that there's one type which may surprise you: decimal. While it doesn't consider leading zeroes, it does have a notion of trailing zeroes (implicitly in the way it's stored), so 1.0m and 1.00m are distinguishable values.
Basically you want to add padding zeros.
string format specifier has a very simple method to this.
string valueAfterpadding;
int value = 23;
valueAfterpadding = value.ToString("D4");
Console.WriteLine(valueAfterpadding );
this solve your problem. just google it.
Integer wont accept leading zeros, it will only hold the real value of the integer.
The best we to have leading zeros is to convert it to string.
If you need a 4 digit value always, use the .ToString formatting to add leading 0's.
int value = 23;
var result = value.ToString("0000");
or if you want to have a leading 00 to any number, better append 00 to the string equivalent of the integer.
int value = 23;
var result = "00" + value.ToString();
This is not a programming issue. Numbers have no leading zeroes.
There are two things here that you can do:
If it is a number, then format it on the way out.
If it is something like a code (article number etc.) - those are NOT NUMBERS.
The second point is important. Things like social security numbers, part numbers etc. are strings - with only numeric characters allowed. You never add or subtract them and you must be prepared for format changes. They are not integers or any other number form to start with.

Which data structure(or type) would be useful for defining the digit amount of a number?

Hi there fellow programmers,
I know that should be easy but I need to define the digit amount of a number for trying all the combinations in a project. The digit number shouldn't be affected by users actions because the change of the digit amount causes "Index out of range" error. (Yes, I am using arrays for this)
Let's say, I have to use four digit number.
int Nmr=1000;
Nmr--;
Console.Write(Nmr);// The output will be 999 but I need 0999
Using string type and if statements could lead to an alternative solution...
int Nmr=1000;
Nmr--;
string number=Nmr.ToString();
if (Nmr<1000) number="0"+number;
if (Nmr<100) number="00"+number;
if (Nmr<10) number="000"+number;
Console.Write(Nmr); //That gives me 0999
But then, it gives me complexity and unneccessary time loss which I wouldn't want to encounter. I am not even talking about the greater values.
So, what would you suggest?
Edit: Both ToString("0000") and PadLeft methods are useful.
Thank you Mateus Coutinho Martino and Blorgbeard. =)
You can specify a format when calling ToString - e.g.
string number = Nmr.ToString("0000");
See the docs: Int32.ToString(string) and Custom Numeric Format Strings.
Well, do with PadLeft method of String class ...
int Nmr=1000;
Nmr--;
Console.Write(Nmr.ToString().PadLeft(4,'0')); //That gives you ever four digits.
Or if you prefer better explained ...
int Nmr=1000;
Nmr--;
String number = Nmr.ToString();
Console.Write(number.PadLeft(4,'0')); // four digits again;
The "0" custom format specifier serves as a zero-placeholder symbol.
Here's a little idea for you:
double numberS;
numberS = 123;
Console.WriteLine(numberS.ToString("00000"));
Console.WriteLine(String.Format("{0:00000}", value));
// Displays 00123
You can look at https://msdn.microsoft.com/en-us/library/0c899ak8.aspx for more.

ReadByte function does it work correctly

In FileStream class we have ReadByte method well actually it does not work as I supposed
why ReadByte ignore "nonsignificant" zeros from beginning of byte? How could I avoid that ?
as someone mentioned in comments, yes im trying to convert it to string
dane.Append(Convert.ToString((byte)w,2));
So is it ToString function skipping zeros?
The numbers are the same; only the ToString is the issue
dane.Append(Convert.ToString((byte)w,2).PadLeft(8, '0'));
ReadByte reads a byte. The result it returns is a number. When you say "nonsignificant zeroes", presumably you mean zero digits. But digits are not properties of numbers, they're properties of textual depictions of numbers in base ten (or sixteen).
"8" and "08" are two different ways to depict in digits the same number. If you aren't seeing the number depicted the way you want it, the issue is in the code that chose who to depict it.

Regex to validate several ranges of values (.NET)

I have the option to use a regex to validate some values and I would like to know the best way to do it.
I have several ranges (not in the same regex/validation) such as 1-9 (this is easy :P), and:
1-99
1-999
1-9999
Also, I need to check for leading zeros, so, 0432 is a possible match.
I know that Regex might not be the best approach for this, but it's what I have, and it's part of a framework I have to use.
There is a fundamental flaw with all other answers!!
bool isMatch = Regex.IsMatch("9999", #"\d{1,3}");
Returns true although the number is not a 1-3 digit number. That is because part of the word matches the expression.
You needs to use:
bool isMatch = Regex.IsMatch("9999", #"^\d{1,n}$");
Where n is the maximum number of digits.
UPDATE
In order to make sure it is not zero, change it to below:
bool isMatch = Regex.IsMatch("9999", #"(^\d{2,n}$)|[1-9]");
UPDATE 2
It still would not work if we have 00 or 000 or 0000. My brain hurts, I will have a look again later. We can do it as two expressions ("(^\d{2,n}$)|[1-9]" and NOT (0)|(00)|(000)|(0000)) but that probably is not accepted as a SINGLE regex answer.
The easy way (n is the amount of numbers):
[0-9]{n}
I’m not 100% clear on what you want but perhaps something like this?
\d{1,2}
This is the equivalent to \d\d? and will match any one- or two-digit number, that is any number from 0 to 99, including leading zeros.
If you really want to exclude 0, then things get a lot more complicated.
Basically, you need to check for 1–9 and 01–09 explicitly. The third group of allowed numbers will have two digits that do not start with a zero:
0?[123456789]|[123456789]\d
Now the part before the | will check whether it’s a number below 10, with optional leading zero. The second alternative will check whether it’s a two-digit number not starting with a zero.
The rest of the ranges can be checked by extending this.

C# - Math.Round

I am trying to understand how to round to the nearest tenths position with C#. For instance, I have a value that is of type double. This double is currently set to 10.75. However, I need to round and then truncate everything past the tenths position. In this case, I am seeking a value of 10.8. How do I round to the tenths position in C#?
Thank you!
Math.Round(yourNumber, 1)
The second parameter is number of decimal places to round to. In your case you want 1 decimal place as an end result.
You simply need to use the overload of Math.Round that takes the decimals parameter.
Math.Round(10.75, 1) // returns 10.8
Just for comparison:
Math.Round(10.75) // returns 11
Math.Round(10.75, 0) // returns 11
Math.Round(10.75, 2) // returns 10.75
Since you Used Math.Round() in your title, I'm going to assume you've already tried the basic Math.Round(10.75,1) approach and it returns something you don't expect. With that in mind, I suggest looking at some of the different overloads for the function, specifically one that accepts a MidPointRounding enum:
http://msdn.microsoft.com/en-us/library/f5898377.aspx
Do you really need to round it, or can you just format it for printing but allow the variable itself to hold its precision? Something like:
decimal value = 10.75;
value.ToString ("#.#");
If you just want to "cut" everything after the first decimal, this shoudl work :
return Math.Round(value * 10)/10

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