Error in function page.extract_words()

[VasiliyLukin]

Hi,
page.extract_words() fails with TypeError: '<' not supported between instances of 'str' and 'NoneType'.
Issue with page no. 51 in an attached file
gpfra2012_protocol.pdf
I use v0.6.0.

` in find_rects(page)
1 def find_rects(page):
2 rects = []
----> 3 words = page.extract_words()
4
5 markers = [

C:\Program Files (x86)\Microsoft Visual Studio\Shared\Anaconda3_64\lib\site-packages\pdfplumber\page.py in extract_words(self, **kwargs)
173 def extract_words(self, **kwargs):
174
--> 175 return utils.extract_words(self.chars, **kwargs)
176
177 def find_text_edges(self, *args, **kwargs):

C:\Program Files (x86)\Microsoft Visual Studio\Shared\Anaconda3_64\lib\site-packages\pdfplumber\utils.py in extract_words(chars, x_tolerance, y_tolerance, fontsize_tolerance, keep_blank_chars, match_fontsize, match_fontname)
226 doctop_clusters = list(itertools.chain.from_iterable(
227 cluster_objects(chars, "fontname", 0)
--> 228 for chars in doctop_clusters))
229
230 nested = [ get_line_words(line_chars, tolerance=x_tolerance)

C:\Program Files (x86)\Microsoft Visual Studio\Shared\Anaconda3_64\lib\site-packages\pdfplumber\utils.py in (.0)
226 doctop_clusters = list(itertools.chain.from_iterable(
227 cluster_objects(chars, "fontname", 0)
--> 228 for chars in doctop_clusters))
229
230 nested = [ get_line_words(line_chars, tolerance=x_tolerance)

C:\Program Files (x86)\Microsoft Visual Studio\Shared\Anaconda3_64\lib\site-packages\pdfplumber\utils.py in cluster_objects(objs, attr, tolerance)
47 objs = to_list(objs)
48 values = map(attr_getter, objs)
---> 49 cluster_dict = make_cluster_dict(values, tolerance)
50
51 get_0, get_1 = itemgetter(0), itemgetter(1)

C:\Program Files (x86)\Microsoft Visual Studio\Shared\Anaconda3_64\lib\site-packages\pdfplumber\utils.py in make_cluster_dict(values, tolerance)
32 def make_cluster_dict(values, tolerance):
33 tolerance = decimalize(tolerance)
---> 34 clusters = cluster_list(set(values), tolerance)
35
36 nested_tuples = [ [ (val, i) for val in value_cluster ]

C:\Program Files (x86)\Microsoft Visual Studio\Shared\Anaconda3_64\lib\site-packages\pdfplumber\utils.py in cluster_list(xs, tolerance)
14 def cluster_list(xs, tolerance=0):
15 tolerance = decimalize(tolerance)
---> 16 if tolerance == 0: return [ [x] for x in sorted(xs) ]
17 if len(xs) < 2: return [ [x] for x in sorted(xs) ]
18 groups = []

TypeError: '<' not supported between instances of 'str' and 'NoneType'

[jsvine]

Thanks for identifying this bug, @VasiliyLukin! Was caused by some character objects not explicitly having a font name. Should now be fixed both in master and in the v0.6.0 branch. Feel free to re-open this issue, though, if the problem persists.