short and sweet, this python snippet will return a list containing your filtered directory
import re
import os
filter = ".*" + searchstr + ".*"
m = re.compile(filter,re.I) #if you want to ignore case use re.I, otherwise remove it
filter(m.search,os.listdir(os.getcwd()))
#that's it, you can see that the reason for compiling the regex is so you can use m.search as a function pointer which accepts the list of all items in the directory