User reported amounts losing trailing zeros — 4.50 rendering as
4.5, 1000.00 as 1000 — on the same statement. Classic float
display issue: Python's native ``repr(4.5)`` drops the
``.0``, and pandas / Streamlit happily show that
inconsistency cell-by-cell.
Two layers of fix, internal type stays ``float`` for arithmetic:
**Display.** ``st.column_config.NumberColumn(format="%.2f")``
applied programmatically to every ``amount_*`` column on the
data_editor. Every numeric amount now shows with exactly two
decimal places regardless of trailing zeros.
**CSV export.** Pandas' default float-to-CSV writer also drops
trailing zeros (the same issue an accountant would see when
opening the file in Excel). Before serialising, each amount
column is mapped through the new ``format_amount`` helper —
returns ``f"{v:.2f}"`` for numerics, empty string for
None/NaN/inf, ``str(value)`` for booleans (guards the
``True → "1.00"`` foot-gun since ``bool`` is an ``int``
subclass), and passes through any string the scanner kept
because parsing failed (e.g. ``(4.50)`` when parens-negative is
off — user can correct in the editor before re-exporting).
``format_amount`` lives in ``src/pdf_extract.py`` so it's
testable in isolation (the page module can't easily be unit
tested because of its Streamlit import chain). 8 new tests
cover the trailing-zeros case, negatives, None/empty,
string-passthrough, bool guard, NaN/inf, and the ``places``
parameter.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Michael
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