Python Pitfalls: References to the same dictionary

Today, I tried to build a dictionary which contains the contents of a list as keys and empty dictionarys as values. First, I went with the method dict.fromkeys(seq, [value]), then I filled the sub-dictionaries in a for loop, like this:

mydict = dict.fromkeys(lstLabels, {}) for strLabel in dict.keys(): mydict[strLabel][strLabel] = "x"

What I ended up with was that the sub-dictionaries referenced by the keys from lstLabels all referenced to the same dictionary instance. What this means is, that whenever you add something to dict[lstLabels[0]], it appears in dict[lstLabels[1]], too, and so on.

The correct way to accomplish what I wanted - different instances of subdirectories - was this:

for strLabel in lstLabels: mydict[strLabel] = {} mydict[strLabel][strLabel] = "x"

Apparently, the dict.fromkeys() method does something like lstFail = [[] * 3]

Are there more elegant ways to create a dictionary with subdictionarys based on a list of strings than the one presented?