It’s important to pick good names for things. This can be hard, and so it’s worth putting some time and thought into it.

As a general rule, don’t use spaces, either in variable names (that is, the names of the columns in your data) or in file names. They make programming harder: the analyst will need to surround everything in double quotes, like "glucose 6 weeks" rather than just writing glucose_6_weeks. Where you might use spaces, use underscores or perhaps hyphens. But don’t use a mixture of underscores and hyphens; pick one and be consistent.

Be careful about extraneous spaces (say, at the beginning or end of a variable name). “glucose” is different from “glucose ” (with an extra space at the end). Extraneous spaces can cause headaches later.

Avoid special characters, too. (Except for underscores and hyphens; they’re okay.) Other symbols ($, @, %, #, &, *, (, ), !, etc.) often have special meaning in programming languages, and so they can be harder to handle. They’re also a bit harder to type.

The main principle in choosing names, whether for variables or for file names, is short, but meaningful. So not too short.

The Data Carpentry lesson on using spreadsheets has a nice table with good and bad example variable names:

good name	good alternative	avoid
Max_temp	MaxTemp1	Maximum Temp (°C)
Precipitation	Precipitation_mm	precmm
Mean_year_growth	MeanYearGrowth	Mean growth/year
sex	sex	M/F
weight	weight	w.
cell_type	CellType	Cell type
first_observation	Observation_01	1st Obs.

I agree with all of this. I’d maybe cut down on some of the capitalization. So maybe max_temp, precipitation, and mean_year_growth.

Finally, never include “final” in a file name. You’ll invariably end up with “final_ver2”. I can’t say that without referring to this PHD comic:

phdcomics.com

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