327 lines
11 KiB
Python
327 lines
11 KiB
Python
from __future__ import division
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import os
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import types
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import copy_reg
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import logging
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import numpy as np
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from .table import Table
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from .utils import get_row_index, get_score, count_empty, encode_list, pdf_to_text
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__all__ = ['Stream']
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def _reduce_method(m):
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if m.im_self is None:
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return getattr, (m.im_class, m.im_func.func_name)
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else:
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return getattr, (m.im_self, m.im_func.func_name)
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copy_reg.pickle(types.MethodType, _reduce_method)
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def _group_rows(text, ytol=2):
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"""Groups text objects into rows using ytol.
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Parameters
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----------
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text : list
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List of text objects.
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ytol : int
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Tolerance to account for when grouping rows
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together. (optional, default: 2)
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Returns
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-------
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rows : list
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List of grouped text rows.
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"""
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row_y = 0
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rows = []
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temp = []
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for t in text:
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# is checking for upright necessary?
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# if t.get_text().strip() and all([obj.upright for obj in t._objs if
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# type(obj) is LTChar]):
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if t.get_text().strip():
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if not np.isclose(row_y, t.y0, atol=ytol):
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rows.append(sorted(temp, key=lambda t: t.x0))
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temp = []
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row_y = t.y0
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temp.append(t)
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rows.append(sorted(temp, key=lambda t: t.x0))
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__ = rows.pop(0) # hacky
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return rows
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def _merge_columns(l, mtol=0):
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"""Merges overlapping columns and returns list with updated
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columns boundaries.
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Parameters
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----------
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l : list
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List of column x-coordinates.
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Returns
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-------
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merged : list
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List of merged column x-coordinates.
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"""
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merged = []
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for higher in l:
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if not merged:
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merged.append(higher)
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else:
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lower = merged[-1]
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if mtol > 0:
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if (higher[0] <= lower[1] or
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np.isclose(higher[0], lower[1], atol=mtol)):
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upper_bound = max(lower[1], higher[1])
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lower_bound = min(lower[0], higher[0])
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merged[-1] = (lower_bound, upper_bound)
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else:
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merged.append(higher)
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elif mtol < 0:
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if higher[0] <= lower[1]:
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if np.isclose(higher[0], lower[1], atol=abs(mtol)):
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merged.append(higher)
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else:
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upper_bound = max(lower[1], higher[1])
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lower_bound = min(lower[0], higher[0])
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merged[-1] = (lower_bound, upper_bound)
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else:
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merged.append(higher)
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return merged
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def _get_column_index(t, columns):
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"""Gets index of the column in which the given object falls by
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comparing their co-ordinates.
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Parameters
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----------
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t : object
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columns : list
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Returns
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-------
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c : int
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"""
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offset1, offset2 = 0, 0
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lt_col_overlap = []
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for c in columns:
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if c[0] <= t.x1 and c[1] >= t.x0:
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left = t.x0 if c[0] <= t.x0 else c[0]
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right = t.x1 if c[1] >= t.x1 else c[1]
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lt_col_overlap.append(abs(left - right) / abs(c[0] - c[1]))
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else:
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lt_col_overlap.append(-1)
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if len(filter(lambda x: x != -1, lt_col_overlap)) == 0:
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logging.warning("Text doesn't fit any column.")
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c_idx = lt_col_overlap.index(max(lt_col_overlap))
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if t.x0 < columns[c_idx][0]:
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offset1 = abs(t.x0 - columns[c_idx][0])
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if t.x1 > columns[c_idx][1]:
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offset2 = abs(t.x1 - columns[c_idx][1])
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Y = abs(t.y0 - t.y1)
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charea = abs(t.x0 - t.x1) * abs(t.y0 - t.y1)
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error = (Y * (offset1 + offset2)) / charea
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return c_idx, error
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def _add_columns(cols, text, ytolerance):
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if text:
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text = _group_rows(text, ytol=ytolerance)
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elements = [len(r) for r in text]
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new_cols = [(t.x0, t.x1)
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for r in text if len(r) == max(elements) for t in r]
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cols.extend(_merge_columns(sorted(new_cols)))
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return cols
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def _get_table_bounds(rows):
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x0 = min([t.x0 for r in rows for t in r])
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x1 = max([t.x1 for r in rows for t in r])
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y0 = min([t.y0 for t in rows[-1]])
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y1 = max([t.y1 for t in rows[0]])
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return x0, x1, y0, y1
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def _join_columns(cols, text_x_min, text_x_max):
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cols = sorted(cols)
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cols = [(cols[i][0] + cols[i - 1][1]) / 2 for i in range(1, len(cols))]
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cols.insert(0, text_x_min)
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cols.append(text_x_max)
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cols = [(cols[i], cols[i + 1])
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for i in range(0, len(cols) - 1)]
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return cols
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class Stream:
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"""Stream algorithm
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Groups text objects into rows and guesses number of columns
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using mode of the number of text objects in each row.
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The number of columns can be passed explicitly or specified by a
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list of column x-coordinates.
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Parameters
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----------
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pdfobject : camelot.pdf.Pdf
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ncolumns : int
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Number of columns. (optional, default: 0)
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columns : string
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Comma-separated list of column x-coordinates.
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(optional, default: None)
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ytol : int
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Tolerance to account for when grouping rows
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together. (optional, default: 2)
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debug : bool
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Debug by visualizing textboxes. (optional, default: False)
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Attributes
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----------
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tables : dict
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Dictionary with page number as key and list of tables on that
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page as value.
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"""
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def __init__(self, ncolumns=0, columns=None, ytol=2, mtol=2,
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pdf_margin=(2.0, 0.5, 0.1), debug=False):
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self.method = 'stream'
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self.ncolumns = ncolumns
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self.columns = columns
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self.ytol = ytol
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self.mtol = mtol
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self.char_margin, self.line_margin, self.word_margin = pdf_margin
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self.debug = debug
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def get_tables(self, pdfname):
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"""Returns all tables found in given pdf.
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Returns
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-------
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tables : dict
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Dictionary with page number as key and list of tables on that
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page as value.
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"""
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__, text, width, height = pdf_to_text(pdfname, self.char_margin,
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self.line_margin, self.word_margin)
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bname, __ = os.path.splitext(pdfname)
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if not text:
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logging.warning("{0}: PDF has no text. It may be an image.".format(
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os.path.basename(bname)))
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return None
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text.sort(key=lambda x: (-x.y0, x.x0))
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if self.debug:
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self.debug_text = [(t.x0, t.y0, t.x1, t.y1) for t in text]
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return None
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rows_grouped = _group_rows(text, ytol=self.ytol)
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elements = [len(r) for r in rows_grouped]
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row_mids = [sum([(t.y0 + t.y1) / 2 for t in r]) / len(r)
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if len(r) > 0 else 0 for r in rows_grouped]
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rows = [(row_mids[i] + row_mids[i - 1]) / 2 for i in range(1, len(row_mids))]
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bounds = _get_table_bounds(rows_grouped)
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rows.insert(0, bounds[3])
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rows.append(bounds[2])
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rows = [(rows[i], rows[i + 1])
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for i in range(0, len(rows) - 1)]
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guess = False
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if self.columns:
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# user has to input boundary columns too
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# take (0, width) by default
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# similar to else condition
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# len can't be 1
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cols = self.columns.split(',')
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cols = [(float(cols[i]), float(cols[i + 1]))
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for i in range(0, len(cols) - 1)]
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else:
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if self.ncolumns:
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ncols = self.ncolumns
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cols = [(t.x0, t.x1)
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for r in rows_grouped if len(r) == ncols for t in r]
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cols = _merge_columns(sorted(cols), mtol=self.mtol)
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if len(cols) != self.ncolumns:
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logging.warning("{}: The number of columns after merge"
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" isn't the same as what you specified."
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" Change the value of mtol.".format(
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os.path.basename(bname)))
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cols = _join_columns(cols, bounds[0], bounds[1])
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else:
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guess = True
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ncols = max(set(elements), key=elements.count)
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len_non_mode = len(filter(lambda x: x != ncols, elements))
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if ncols == 1 and not self.debug:
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# no tables detected
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logging.warning("{}: Only one column was detected, the PDF"
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" may have no tables. Specify ncols if"
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" the PDF has tables.".format(
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os.path.basename(bname)))
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cols = [(t.x0, t.x1)
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for r in rows_grouped if len(r) == ncols for t in r]
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cols = _merge_columns(sorted(cols), mtol=self.mtol)
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inner_text = []
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for i in range(1, len(cols)):
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left = cols[i - 1][1]
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right = cols[i][0]
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inner_text.extend([t for t in text if t.x0 > left and t.x1 < right])
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outer_text = [t for t in text if t.x0 > cols[-1][1] or t.x1 < cols[0][0]]
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inner_text.extend(outer_text)
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cols = _add_columns(cols, inner_text, self.ytol)
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cols = _join_columns(cols, bounds[0], bounds[1])
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pdf_page = {}
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page_tables = {}
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table_info = {}
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table = Table(cols, rows)
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rerror = []
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cerror = []
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for row in rows_grouped:
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for t in row:
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try:
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r_idx, rass_error = get_row_index(t, rows)
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except ValueError as e:
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# couldn't assign LTTextLH to any cell
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vprint(e.message)
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continue
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try:
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c_idx, cass_error = _get_column_index(t, cols)
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except ValueError as e:
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# couldn't assign LTTextLH to any cell
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vprint(e.message)
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continue
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rerror.append(rass_error)
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cerror.append(cass_error)
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table.cells[r_idx][c_idx].add_text(
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t.get_text().strip('\n'))
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if guess:
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score = get_score([[33, rerror], [33, cerror], [34, [len_non_mode / len(elements)]]])
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else:
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score = get_score([[50, rerror], [50, cerror]])
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table_info['score'] = score
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ar = table.get_list()
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ar = encode_list(ar)
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table_info['data'] = ar
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empty_p, r_nempty_cells, c_nempty_cells = count_empty(ar)
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table_info['empty_p'] = empty_p
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table_info['r_nempty_cells'] = r_nempty_cells
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table_info['c_nempty_cells'] = c_nempty_cells
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table_info['nrows'] = len(ar)
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table_info['ncols'] = len(ar[0])
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page_tables['table_1'] = table_info
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pdf_page[os.path.basename(bname)] = page_tables
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return pdf_page |