Adding a 0 if number is less than 10

Question

Possible Duplicate:
C# int ToString format on 2 char int?

Sorry for the simplicity, but this one is eluding me. Pretty much I have a list of 36 records, and if the id is less than 10, I need it to return 01, 02, 03... 09, instead of 1, 2, 3... 9.

Here is the code I have so far and I would have thought this would work. This is C# .NET:

for (int i = 1; i <= 36; i++)
{
    if (i.ToString().Length == 1)
    {
        i.ToString().PadLeft(2,'0');
    }

    Response.Write("Test: " + i);
}

Any help would be appreciated, thanks in advance!

See, I don't like closing this while becaues the question was about the padding, the issue the OP was having had nothing to do with that, ironically he was doing that correct, he just wasn't assigning the value properly. — CaffGeek, Sep 18 '12 at 16:01
@CaffGeek the problem is no one with the same problem will ever see the right answer because the question is not asking right thing. It probably could get salvaged to reask the proper question, but then you potentially invalidate at least 1 answer that didn't address the OP's real problem — psubsee2003, Sep 18 '12 at 16:09

score 22 · Answer 1 · answered Sep 18 '12 at 15:48

22

You don't need IF, use ToString

int i = 5;

i.ToString("00"); //returns 05

answered Sep 18 '12 at 15:48

Alberto León

2,879
2
25
24

score 14 · Accepted Answer · edited Apr 06 '20 at 08:43

Your problem is i is still an integer, it needs to be assigned to a string

  for (int i = 1; i <= 36; i++)
    {
        var iString = i.ToString();

        if(iString.Length == 1)
        {
            iString = iString.PadLeft(2,'0'); //RIGHT HERE!!!
        }
        Response.Write("Test: " + iString);
    }

However, much of this code is superflous, the if statement is not needed. Pad will only ped with zeroes up to the length (2) given. If it's already 2 or more characters long, it won't pad anything. All you need is this

    for (int i = 1; i <= 36; i++)
    {
        var iString = i.ToString().PadLeft(2,'0');
        Response.Write("Test: " + iString);
    }

For that matter, the variable is no longer needed.

    for (int i = 1; i <= 36; i++)
    {
        Response.Write("Test: " + i.ToString().PadLeft(2,'0'));
    }

And if you'll be padding with zeroes all the time, and not some other character, you could just do this

    for (int i = 1; i <= 36; i++)
    {
        Response.Write("Test: " + i.ToString("00"));
    }

And you should get into the habit of using string.Format

    for (int i = 1; i <= 36; i++)
    {
        Response.Write(string.Format("Test: {0}", i.ToString("00")));
    }

And to simplify the string.Format even further:

    for (int i = 1; i <= 36; i++)
    {
        Response.Write(string.Format("Test: {0:00}", i));
    }

score 4 · Answer 3 · answered Sep 18 '12 at 15:47

4

You can try with

var list = new List<string>();
for (int i = 1; i <= 36; i++)
{
    var result = string.Empty; 
    if(i < 10)
    {
         result = string.Format("0{0}", i);
    }
    else
    {
        result = i.ToString();
    }
    list.Add(result);
}

Nota : Concat your values nefore call Response.Redirect

answered Sep 18 '12 at 15:47

Aghilas Yakoub

28,516
5
46
51

Response.Redirect??? what are you talking about – CaffGeek Sep 18 '12 at 15:50
@Tony Yes i added this condition (i<10) – Aghilas Yakoub Sep 18 '12 at 15:50
just concat his values before call Response.Redirect – Aghilas Yakoub Sep 18 '12 at 15:51

score 3 · Answer 4 · answered Sep 18 '12 at 15:48

You are not doing anything with the following line:

i.ToString().PadLeft(2,'0');

i is still just an integer, and its string representation is not going to have a 0 in front of it when you use it later. You would need to save a string of the value to print later.

AndreyAkinshin · Answer 5 · 2012-09-18T15:54:48.743

You needn't check i.ToString().Length == 1:

for (int i = 1; i <= 36; i++)    
    Response.Write("Test: " + i.ToString().PadLeft(2,'0'));

Look to PadLeft in MSDN for clarification. Common signature:

public string PadLeft(int totalWidth, char paddingChar)

Also you can use String.Format:

for (int i = 1; i <= 36; i++)    
    Response.Write("Test: " + i.ToString("00"));

Another way - use LINQ:

foreach (var number in Enumerable.Range(1, 36).Select(i => i.ToString("00")))
  Response.Write("Test: " + number);

score 2 · Answer 6 · answered Sep 18 '12 at 15:47

You're simply converting i to string and throwing away the result. In Response.Write("Test: " + i); you're printing i instead of its conversion to string. Try:

for (int i = 1; i <= 36; i++)
{
    if (i.ToString().Length == 1)
    {
           Response.Write(i.ToString().PadLeft(2,'0'));
    }
}

Adding a 0 if number is less than 10

6 Answers6