Naming conventions. Method or variable names containing numbers as a words

Question

I can't find even couple of words about containing numbers in names of variables or on methods. Does anyone have any authoritative information about such cases:

• string2map
• its4me
• etc... Exactly using number as a word but not number as a number. Is it acceptable? Not acceptable, stupidly, professional or not. Please argue your opinion.

Answer 1

I haven't found any information either but below are my own thoughts.

Using a digit in an identifier which happens 2 be pronounced in the same way as a word is just silly word play. It also makes the meaning of the identifier ambiguous - does char2old mean that a character is too old, is it an old version of char2 or is it a conversion? It's fun however to come up with names like a10sorFlow, the2lbox, my4mula but they are best avoided.

When it comes to using numbers 1 to N at the end of equally named identifiers, it is probably better to use an array instead if N > 2. Also, when N = 2 there are often clearer names that can be used, like leftCircle and rightCircle instead of circle1 and circle2, or currentChar and nextChar instead of char1 and char2.

Here is a good general guide for naming variables:

Identifier kind	Word class	Example
Boolean variable or pure function	Last word is an adjective	doorClosed, TablePrepared
Non-boolean variable or pure function	Last word is a noun	closedDoor, PreparedTable
Non-pure function (has side-effects)	First word is a verb	CloseDoor, PrepareTable