Replacing list item with contents of another list

Question

Similar to this question, but instead of replacing one item with another, I\'d like to replace any occurrences of one item with the contents of a list.

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Answer 1

If you enumerate backwards, you can extend the list as you go because the items you move have already gone through the enumeration.

>>> orig = [ 'a', 'b', 'c', 'd', 'c' ]
>>> repl = [ 'x', 'y', 'z' ]
>>> desired = [ 'a', 'b', 'x', 'y', 'z', 'd', 'x', 'y', 'z' ]
>>> for i in xrange(len(orig)-1, -1, -1):
...     if orig[i] == 'c':
...             orig[i:i+1] = repl
... 
>>> orig
['a', 'b', 'x', 'y', 'z', 'd', 'x', 'y', 'z']