How to name variables

Question

• What rules do you use to name your variables?
• Where are single letter vars allowed?
• How much info do you put in the name?
• How about for exam

Answer 1

I always use single letter variables in for loops, it's just nicer-looking and easier to read.

A lot of it depends on the language you're programming in too, I don't name variables the same in C++ as I do in Java (Java lends itself better to the excessively long variable names imo, but this could just a personal preference. Or it may have something to do with how Java built-ins are named...).

Answer 2

What rules do you use to name your variables?

Typically, as I am a C# developer, I follow the variable naming conventions as specified by the IDesign C# Coding Standard for two reasons

1) I like it, and find it easy to read. 2) It is the default that comes with the Code Style Enforcer AddIn for Visual Studio 2005 / 2008 which I use extensively these days.

Where are single letter vars allows?

There are a few places where I will allow single letter variables. Usually these are simple loop indexers, OR mathematical concepts like X,Y,Z coordinates. Other than that, never! (Everywhere else I have used them, I have typically been bitten by them when rereading the code).

How much info do you put in the name?

Enough to know PRECISELY what the variable is being used for. As Robert Martin says:

The name of a variable, function, or class, should answer all the big questions. It should tell you why it exists, what it does, and how it is used. If a name requires a comment, then the name does not reveal its intent. From Clean Code - A Handbook of Agile Software Craftsmanship

Answer 3

I do a lot of php in nowadays, It was not always like that though and I have learned a couple of tricks when it comes to variable naming.

//this is my string variable $strVar = "";

//this would represent an array $arrCards = array();

//this is for an integer $intTotal = NULL:

//object $objDB = new database_class();

//boolean $blValid = true;

Answer 4

I work in MathCAD and I'm happy because MathCAD gives me increadable possibilities in naming and I use them a lot. And I can`t understand how to programm without this. To differ one var from another I have to include a lot of information in the name,for example:

1.On the first place - that is it -N for quantity,F for force and so on

2.On the second - additional indices - for direction of force for example

3.On the third - indexation inside vector or matrix var,for convinience I put var name in {} or [] brackets to show its dimensions.

So,as conclusion my var name is like N.dirs / Fx i.row / {F}.w.(i,j.k) / {F}.w.(k,i.j). Sometimes I have to add name of coordinate system for vector values {F}.{GCS}.w.(i,j.k) / {F}.{LCS}.w.(i,j.k)

And as final step I add name of the external module in BOLD at the end of external function or var like Row.MTX.f([M]) because MathCAD doesn't have help string for function.

Answer 5

function startEditing(){
   if (user.canEdit(currentDocument)){
      editorControl.setEditMode(true);
      setButtonDown(btnStartEditing);
   }
 }

Should read like a narrative work.

Answer 6

In DSLs and other fluent interfaces often variable- and method-name taken together form a lexical entity. For example, I personally like the (admittedly heretic) naming pattern where the verb is put into the variable name rather than the method name. @see 6th Rule of Variable Naming

Also, I like the spartan use of $ as variable name for the main variable of a piece of code. For example, a class that pretty prints a tree structure can use $ for the StringBuffer inst var. @see This is Verbose!

Otherwise I refer to the Programmer's Phrasebook by Einar Hoest. @see http://www.nr.no/~einarwh/phrasebook/