concatenate string, with different first and last iteration

Question

Good day. My code works but I think there is a better way to do this. Like string pattern or string manipulation. I'm not yet familiar with both terms.

The goal is to get "=A1-A2-B3-D4-WHATEVER STRING=". From array of strings.

The code is :

string[] arr = { "A1", "A2", "B3", "D4", "WHATEVER STRING"}; // can be any string value
string newString = "=";
for (int i = 0; i < arr.Length; i++) {
 if (i == arr.Length-1) {
 newString += arr[i].ToString() + "="; 
 } else {
 newString += arr[i].ToString() + "-";
 }
}

• Mast: To the reviewers: while not particularly well-written, I do think this question is simple enough that it can't be closed for Missing Review Context. Please notify me if you disagree.

Answer 1

You should use String.Join() here. Its easier to read and shorter as well.

Like

string[] arr = { "A1", "A2", "B3", "D4", "WHATEVER STRING" }; // can be any string value
string result = "=" + string.Join("-", arr) + "=";

Answer 2

Another simpler and more universal way than the original code in the OP (without using String.Join()) would be

string[] arr = { "A1", "A2", "B3", "D4", "WHATEVER STRING"}; // can be any string value
string newString = "";
foreach (string elem in arr) {
 if(newString <> "") {
 newString += "-"
 }
 newString += elem; // ToString() is not needed in this case
}
newString = "=" + newString + "=";

I often use that pattern in the foreach (or other kind of) loop to concatenate strings with a delimiter. This works in many programming languages, which don't offer the functionality of C#'s String.Join(), or also when you need some ToString() operation for the array elements (e.g. int values).

• Rick Davin: I am the downvoter and usually do not DV. (1) I strongly disagree that this is simpler. When the framework offers a short, performant method, one should favor it. String.Join is such a method, whereas some LINQ calls are not since they are not the best perfomers. (2) If you do this extra coding, you should use StringBuilder instead of re-creating each freakin' string with each small change.
• πάντα ῥεῖ: @RickDavin 1. I didn't say that this is simpler than using String.Join() (I probably should clarify that). What I meant is that it's simpler and better readable than the OPs original approach 2. As mentioned this approach is quite universal and works with many programming languages (I have to work with a great variety of PLs professionally). 3. That said, not every programming language offers a class like StringBuilder either.