How to get the number of files in a folder as a variable?

Question

Using bash, how can one get the number of files in a folder, excluding directories from a shell script without the interpreter complaining?

With the help of a friend

Answer 1

Expanding on the accepted answer (by Dennis W): when I tried this approach I got incorrect counts for dirs without subdirs in Bash 4.4.5.

The issue is that by default nullglob is not set in Bash and numdirs=(*/) sets an 1 element array with the glob pattern */. Likewise I suspect numfiles=(*) would have 1 element for an empty folder.

Setting shopt -s nullglob to disable nullglobbing resolves the issue for me. For an excellent discussion on why nullglob is not set by default on Bash see the answer here: Why is nullglob not default?

Note: I would have commented on the answer directly but lack the reputation points.