+
+ NUMERIC_FIELDS = set((
+ 'width', 'height', 'tbr', 'abr', 'asr', 'vbr', 'fps', 'filesize', 'filesize_approx',
+ 'upload_year', 'upload_month', 'upload_day',
+ 'duration', 'view_count', 'like_count', 'dislike_count', 'repost_count',
+ 'average_rating', 'comment_count', 'age_limit',
+ 'start_time', 'end_time',
+ 'chapter_number', 'season_number', 'episode_number',
+ ))
+
+ # Missing numeric fields used together with integer presentation types
+ # in format specification will break the argument substitution since
+ # string 'NA' is returned for missing fields. We will patch output
+ # template for missing fields to meet string presentation type.
+ for numeric_field in NUMERIC_FIELDS:
+ if numeric_field not in template_dict:
+ # As of [1] format syntax is:
+ # %[mapping_key][conversion_flags][minimum_width][.precision][length_modifier]type
+ # 1. https://docs.python.org/2/library/stdtypes.html#string-formatting
+ FORMAT_RE = r'''(?x)
+ (?<!%)
+ %
+ \({0}\) # mapping key
+ (?:[#0\-+ ]+)? # conversion flags (optional)
+ (?:\d+)? # minimum field width (optional)
+ (?:\.\d+)? # precision (optional)
+ [hlL]? # length modifier (optional)
+ [diouxXeEfFgGcrs%] # conversion type
+ '''
+ outtmpl = re.sub(
+ FORMAT_RE.format(numeric_field),
+ r'%({0})s'.format(numeric_field), outtmpl)
+