Missing edge value when using explicit vertical and horizontal lines in some cases

[sjainam]

I use table settings like this:
{
"vertical_strategy": "lines",
"horizontal_strategy": "lines"
}

seen in image edge to edge line not drawn in the left side, the line is the move from the edge
and this one cut the value, I found in .debug_tablefinder

[jsvine]

Interesting. It might have something to do with pdfminer.six's layout engine, but it's hard to say for sure without reference to the actual PDF itself.

[sjainam]

Here is pdf
And Output of debug_tablefinder

[jsvine]

Hi @sjainam. I took some time to look into this, and it's a tricky one! If you run this code:

page = pdf.pages[0]
im = page.to_image(resolution = 300)

(
    im.reset()
    .draw_rects(page.rects, stroke = "green", stroke_width = 3, fill = None)
    .draw_lines(page.lines, stroke_width = 3)
)

... you can start to see what's happening:

... which is that there are, slightly inset from the lines, a series of rects in the header. Those objects come first in the PDF, and so the tablefinder uses them as a provisional starting point. Then, because pdfplumber wants to be tolerant of lines that are slightly offset from each other, it "snaps" the nearby vertical line to that x-position.

(Note: the "lines" strategies in the table settings use both literal lines and also the lines indicated by rectangles.)

You can avoid this all by setting snap_tolerance to 0 in your table settings:

{
    "vertical_strategy": "lines",
    "horizontal_strategy": "lines",
    "snap_tolerance": 0,
}

Alternatively, if it doesn't have negative side effects, you could filter out all rects with page.filter(...).