Question

Every once in a while, I need to build a character separated string while looping through a collection. Believe it or not, there is always that first or last separator character that gets in the way! 🙂 Usually, I end up chopping off the extra character, which is another line of code. I could leave with that, but out of curiosity, does anyone have any cool “smooooth” way of doing this? (in C# and/or JavaScript)

Example:

{"Joe", "Jane", "Jim"}

After building comma separated string, we get:

"Joe, Jane, Jim, " or ", Joe, Jane, Jim"

Looking for a cool way to build

"Joe, Jane, Jim"

without any string “chopping” after.

Answer 1

In Javascript it’s easy:

var input = ["Joe", "Jane", "Jim"];

var str = input.join(','); // Output: Joe,Jane,Jim

Most languages have some form of “join” either built-in or in some library:

• Javascript — it’s a native function on the Array prototype
• PHP — implode
• Java — Apache Commons Lang
• C# — String.Join

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By the way, if you are writing such a function, you should just use a check to not prepend the “glue” on the first pass, rather than chopping the string afterward:

var items = ["joe","jane","john"];
var glue = ",";
var s = "";
for (var i=0; i < items.length; i++) {
    if (i != 0) s += glue;
    s += items[i];
}