In a chunk, a cardinal word, tagged as CD, refers to a number, such as 10. These cardinals often occur before or after a noun. For normalization purposes, it can be useful to always put the cardinal before the noun.
The swap_noun_cardinal() function is defined in transforms.py. It swaps any cardinal that occurs immediately after a noun with the noun so that the cardinal occurs immediately before the noun. It uses a helper function, tag_equals(), which is similar to tag_startswith(), but in this case, the function it returns does an equality comparison with the given tag:
def tag_equals(tag):
def f(wt):
return wt[1] == tag
return fNow we can define swap_noun_cardinal():
def swap_noun_cardinal(chunk):
cdidx = first_chunk_index(chunk, tag_equals('CD'))
# cdidx must be > 0 and there must be a noun immediately before it
if not cdidx or not chunk[cdidx-1][1].startswith('NN'):
return chunk
noun, nntag = chunk[cdidx-1]
chunk[cdidx-1]...