Why use a placeholder?

Question

I have a mini project im working on in c#. I'm fairly new to c# and was wondering why I should use a placeholder {0} instead of a +. Are there any differences? Any benefit to using one over the other?

Heres an example-

 public void DisplayMessage()
  {
    Console.WriteLine("Student Name:"+ Name); // Why not this
    Console.WriteLine("Studnt Age: {0}", Age);// instead of this?
  }

Thank you

I see that you aren't trying to micro-optimize and are simply curious. [Here](http://blog.codinghorror.com/the-sad-tragedy-of-micro-optimization-theater/) is something you'll like. — displayName, Feb 29 '16 at 02:09
In C#6 you could also add `Console.WriteLine($"Student Age: {Age}");` — Matt Rowland, Feb 29 '16 at 02:19
Possible duplicate of [String output: format or concat in C#?](http://stackoverflow.com/questions/16432/string-output-format-or-concat-in-c) — Matt Rowland, Feb 29 '16 at 02:20
Complex formatting, multiple fields and tweaking is much easier with string format — Ňɏssa Pøngjǣrdenlarp, Feb 29 '16 at 02:22
@displayName ok so what I got from that is that it really doesnt matter? — user3793369, Feb 29 '16 at 02:27

score 2 · Answer 1 · answered Feb 29 '16 at 02:20

2

Formatted string is clearer than adding strings, especially when you have more than two parameters.

static readonly string UrlFormat = "{0}://{1}/{2}?{3}";  //the format can be reused
var url = string.Format(UrlFormat, scheme, host, path, query);
var anotherUrl = string.Format(UrlFormat, scheme2, host2, path2, query2);
var bad = scheme3 + "://" + host3 + "/" + path3 + "?" + query3;

By the way in C#6 the format can be more pretty:

var urlUsingNewFeature = $"{scheme}://{host}/{path}?{query}";

You can see the maintenance cost between them.

The performance The only advantage of adding strings is that when you adding two strings, it's faster than string formatting.

"Student Name: " + name

is a little faster than

string.Format("Student Name: {0}", name)

I did the benchmark before, adding <=3 strings is faster than using string.Format. But IMO you still should use string.Format, the tiny performance improvement is not that important.

answered Feb 29 '16 at 02:20

Cheng Chen

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Yeah the end user wont notice a difference anyway.. – user3793369 Feb 29 '16 at 02:33
1

@user3793369 But as a backend developer, we should care about those won't be seen by users. Code style and re-usage is quite important. – Cheng Chen Feb 29 '16 at 02:36
@user3793369 Maybe, but still you better stick to the best practices – Konstantin Chernov Feb 29 '16 at 02:50
@user3793369 As a developer staring at that line of code at 10pm following a bad deployment and lots of emergency meetings and triage. I can tell you that the difference is night and day. That is either leaving work during night, or day. – Aron Feb 29 '16 at 04:19

Why use a placeholder?

1 Answers1