Need PHP to sort files ALPHA and NUMERIC

Question

I have a bit of PHP code that grabs a list of files from a directory, and puts them into an array.

I can sort the array alphabetically, and the file list comes out like this:

(Ex A)

CC 2010.pdf
CCP 2010.PDF
RS 1 2010.PDF
RS 15 2010.PDF
RS 2 2010.PDF

I want PHP to sort alphabetically but also take into consideration sorting files with numeric components correctly, such as:

(Ex B)

CC 2010.pdf
CCP 2010.PDF
RS 1 2010.PDF
RS 2 2010.PDF
RS 15 2010.PDF

I do not know what type of sort this is called, but I do notice that Windows sorts files by the first list (A), and that Macs sort files by the more advanced/smarter bottom list (B)

I want to avoid having to add 0's to force the correct sorting order:

(Ex C)

CC 2010.pdf
CCP 2010.PDF
RS 01 2010.PDF
RS 02 2010.PDF
RS 15 2010.PDF

Does anyone know how I can get PHP to sort my array in the logical fashion of example (B)?

Answer 1

Either use natsort(), or if that doesn't fit, define your own logic in a function and use usort(). The term is 'natural sorting'.