Writing an array as a comma separated list to screen

Question

Now it seems like a really simple question and I may just be being thick, but what I'm trying to achieve is basically print an array to screen in the following format:

Item 1, Item 2, Item 3, Item 4

Although I say to screen, as that was the best way I could describe it, I'm actually writing it to the page inside some Javascript.

The way I'm currently going about writing it out is as follows:

for each b in theDates
    Response.Write("'" + b.CallDate + "',")
next

But obviously that returns a string of Item 1, Item 2, Item 3, Item 4,.

Is there a simple way of getting rid of the last comma or am I going about this completely wrong?

Answer 1

Try String.Join (documentation). My VB is rusty, but hopefully you can read this C#:

var datesInQuotes = theDates.Select(date => "'" + date.CallDate + "'");

Response.Write(String.Join(", ", datesInQuotes));

Answer 2

You could use String.Join method. Not sure about VB but something like that:

Response.Write(String.Join(", ", theDates.Select(Function(n) "'" & n.CallDate & "'").ToArray()))

Answer 3

As others have said, String.Join is what you want in this case.

More generically: you've got to either detect when you're at the the last element and not append a comma, or detect when you're at the first element and not prepend a comma.

Typically it's easier to detect when you're at the first, so:

dim firstDone as bool = false
for each b in theDates
    if firstDone then Response.Write (",")
    Response.Write("'" + b.CallDate + "'")
    firstDone = true
next

(Excuse my rusty vb)

Answer 4

No, you aren't wrong - totally.

Loop through theDates and put the data into a string.

After you are done looping, remove the last comma:

myString.Remove(myString.Length - 1, 1);

Response.Write(myString)

A side note: You really shouldn't output to the screen with Response.Write. You should set the text of a server control as your output. A label is perfectly fine. You will notice that your text won't appear where you think it will if you don't.

Answer 5

You could write the comma in front of each item except the first one.

Answer 6

There's no need to String.join this.

st="'"
for each b in theDates
    Response.Write(st + b.CallDate + "'")
    st=", '"
next

Answer 7

I would recommend to do just as you were doing, and then use the Response.Remove(s.Length-1, 1)

Answer 8

In C#:

for (int i = 0; i < theDates.Length; i++)
{
    if (i > 0)
    {
        Response.Write(",");
    }
    Response.Write(theDates[i]);
}