[gbog]

I think I remember that list indexing "list[x]" is o(n), while hash access "hash[x]" is o(1), but my Martelli is not here around.

If I were the guy, I'd first ensure the final escaped result is cached in a key-value store, then I'll check if this func is the real bottleneck. If so, I might also have tried accessing it's content as a byte array. Then, if the file is of Asian origin (ascii being very low minority), I'd bulk escape it with the "&#x%s;" trick. It is rare to have documents with even mix of ascii/latin and other glyph, so I makes sense to have two functions, like he did.

[kbd]

Python's lists are not linked lists. List indexing is O(1).

[gbog]

You are right, double checked in my Martelli.