How can I write these variables into one line of code in C#?

Question

I am new to C#, literally on page 50, and i am curious as to how to write these variables in one line of code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace consoleHelloWorld
{
    class Program
    {
        static void Main(string[] args)
        {

            int mon = DateTime.Today.Month;
            int da = DateTime.Today.Day;
            int yer = DateTime.Today.Year;
            var time = DateTime.Now;

            Console.Write(mon);
            Console.Write("." + da);
            Console.WriteLine("." + yer);
        }
    }
}

I am coming from JavaScript where to do this it would look like this:

document.write(mon+'.'+da+'.'+yer);

Any help here is appreciated.

score 70 · Accepted Answer · edited Jan 10 '19 at 12:33

70

Look into composite formatting:

Console.WriteLine("{0}.{1}.{2}", mon, da, yer);

You could also write (although it's not really recommended):

Console.WriteLine(mon + "." + da + "." + yer);

And, with the release of C# 6.0, you have string interpolation expressions:

Console.WriteLine($"{mon}.{da}.{yer}");  // note the $ prefix.

edited Jan 10 '19 at 12:33

Kols

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answered Mar 14 '13 at 19:29

Jim Mischel

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why is the second way not recommended? – astidham2003 Mar 14 '13 at 19:39
OK great! Thanks I haven't gotten to composite formatting. but I was not closing the ToString with () thus the issue. I am still on types right now but this is valuable insight moving forward... – Erik Grosskurth Mar 14 '13 at 19:43
@AStidham: Not recommended because it's longer, more difficult to see what's going on, more difficult to modify, and less amenable to internationalization. – Jim Mischel Mar 14 '13 at 19:45
@Servy: Good catch. I didn't realize that the compiler would do that. Shows you how often I do string concatenation, doesn't it? – Jim Mischel Mar 14 '13 at 20:00
It's not really the compiler. The `operator +` has three overloads for string concatenation: (string, string), (string, object), and (object, string). The rest of the overloads involve both parameters being numeric types. For the 2nd and 3rd overloads it just calls `ToString` on the object (after null checking it) in the body of the definition. – Servy Mar 14 '13 at 20:02
This is ultimately what I was trying earlier and the problem was that if a string is not separating the int's they would add together. This is why I like the top method more. Thanks guys for your input – Erik Grosskurth Mar 14 '13 at 20:33
I don't have enough rep to do that yet, I have to have 15 points and I only have 11, If you vote up my question then I might have enough to go through them all and up vote them – Erik Grosskurth Mar 19 '13 at 14:26
Just going back looking at old questions and now that i have enough rep I marked it correct. Thanks Jim! – Erik Grosskurth Apr 11 '16 at 15:23

Malcolm O'Hare · Answer 2 · 2013-03-14T19:52:59.893

17

You can do your whole program in one line! Yes, that is right, one line!

Console.WriteLine(DateTime.Now.ToString("yyyy.MM.dd"));

You may notice that I did not use the same date format as you. That is because you should use the International Date Format as described in this W3C document. Every time you don't use it, somewhere a cute little animal dies.

edited Mar 14 '13 at 19:52

answered Mar 14 '13 at 19:33

Malcolm O'Hare

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3

Thanks for that, didn't notice. Will amend this response to chastise him for his poor choice of date format. – Malcolm O'Hare Mar 14 '13 at 19:49
2

Not just a single line, but a single function call :) Console.WriteLine("{0:yyyy.MM.dd}", DateTime.Now); – Stephen Kennedy Jun 17 '13 at 15:27
1

And every time you try to force the International Date Format on a client who wants MM/DD/YYYY, you lose a job. – Jim Mischel Sep 08 '16 at 14:41
for the cute little animals everywhere – user10186832 Oct 12 '22 at 09:32

Mathew Thompson · Answer 3 · 2013-03-14T22:05:43.330

8

You can do pretty much the same as in JavaScript. Try this:

Console.WriteLine(mon + "." + da + "." + yer);

Or you can use WriteLine as if it were a string.Format statement by doing:

Console.WriteLine("{0}.{1}.{2}", mon, da, yer);

which is equivalent to:

string.Format("{0}.{1}.{2}", mon, da, yer);

The number of parameters can be infinite, just make sure you correctly index those numbers (starting at 0).

edited Mar 14 '13 at 22:05

answered Mar 14 '13 at 19:30

Mathew Thompson

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score 5 · Answer 4 · edited Oct 24 '13 at 12:45

5

You should try this one:

Console.WriteLine("{0}.{1}.{2}", mon, da, yet);

See http://www.dotnetperls.com/console-writeline for more details.

edited Oct 24 '13 at 12:45

answered Mar 14 '13 at 19:30

Simon

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score 4 · Answer 5 · answered Mar 14 '13 at 19:30

4

If you want to use something similar to the JavaScript, you just need to convert to strings first:

Console.WriteLine(mon.ToString() + "." + da.ToString() + "." + yer.ToString());

But a (much) better way would be to use the format option:

Console.WriteLine("{0}.{1}.{2}", mon, da, yer);

answered Mar 14 '13 at 19:30

Justin Niessner

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OK great! Thanks I haven't gotten to composite formatting. but I was not closing the ToString with () thus the issue. I am still on types right now but this is valuable insight moving forward... – Erik Grosskurth Mar 14 '13 at 19:43

score 1 · Answer 6 · answered Mar 14 '13 at 19:53

1

You could theoretically do the entire thing as simply:

using System;
using System.Collections.Generic;
using System.Linq; 
using System.Text;

namespace consoleHelloWorld {
class Program {
    static void Main(string[] args) {
       Console.WriteLine(DateTime.Now.ToString("MM.dd.yyyy"));
    }
  }
}

answered Mar 14 '13 at 19:53

apollosoftware.org

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Yes that's great but I wanted to break up the date and get the numbers individually first then reassemble them but you are absolutely right – Erik Grosskurth Mar 14 '13 at 20:13

score 1 · Answer 7 · edited Jul 11 '13 at 02:45

1

 DateTime dateTime = dateTime.Today.ToString("MM.dd.yyyy");

 Console.Write(dateTime);

edited Jul 11 '13 at 02:45

Amit

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answered Jul 11 '13 at 02:24

dhelvana25

11
1

score 1 · Answer 8 · answered May 24 '16 at 12:22

Use $ before " " it will allow to write variables between these brackets

 Console.WriteLine($"{mon}.{da}.{yer}");

The pro way :

  Console.WriteLine($"{DateTime.Today.Month}.{DateTime.Today.Day}.{DateTime.Today.Year}");
  Console.WriteLine($"month{DateTime.Today.Month} day{DateTime.Today.Day} year{DateTime.Today.Year}");

5.24.2016

month5 day24 year2016

score 0 · Answer 9 · answered Mar 14 '13 at 19:30

Give this a go:

string format = "{0} / {1} / {2} {3}";
string date = string.Format(format,mon.ToString(),da.ToString(),yer.ToString();
Console.WriteLine(date);

In fact, there's probably a way to format it automatically without even doing it yourself.

Check out http://msdn.microsoft.com/en-us/library/8kb3ddd4.aspx

score 0 · Answer 10 · answered Mar 14 '13 at 19:34

0

Simple as:

DateTime.Now.ToString("MM.dd.yyyy");

link to MSDN on ALL formatting options for DateTime.ToString() method

http://msdn.microsoft.com/en-us/library/8kb3ddd4.aspx

answered Mar 14 '13 at 19:34

phillk6751

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This did though: DateTime thisDate1 = DateTime.Now; Console.WriteLine("Today is " + thisDate1.ToString("MMMM dd, yyyy") + "."); – Erik Grosskurth Mar 14 '13 at 19:48

How can I write these variables into one line of code in C#?

10 Answers10