Assemble

This article demonstrates how to assemble multiple RTF files into a single RTF or DOCX file using rtflite.

Prerequisites

To enable DOCX support, install rtflite with the docx extra:

pip install rtflite[docx]

Define input files

from pathlib import Path
from rtflite import assemble_docx, assemble_rtf, concatenate_docx

input_files = [
    "example-ae-summary.rtf",
    "example-efficacy.rtf",
]

Assemble into RTF

assemble_rtf(input_files, "combined-rtf.rtf")

Assemble into DOCX with toggle fields

assemble_docx(input_files, "combined-docx.docx")

Open combined-docx.docx in Word and refresh fields to resolve the INCLUDETEXT placeholders. Without opening in Word, the placeholders appear as Error! Reference source not found. because python-docx does not evaluate those fields.

Note

The assemble_docx workflow intentionally mirrors how medical writers paste hyperlinks into CSR sections. After the link is in place, toggling fields or running Update Field in Word reconnects the assembled file to the original TLFs without additional copy-paste work. This hybrid approach, which relies on Word's field codes, is documented in the r4csr book.

Another example to assemble into DOCX with mixed orientation pages (portrait, landscape):

assemble_docx(
    input_files,
    "combined-mixed.docx",
    landscape=[False, True]
)

Open combined-mixed.docx in Word and update fields to pull in the portrait and landscape tables. Until the fields are refreshed, you will see the same Error! Reference source not found. placeholders.

Assemble into DOCX without toggle fields

RTFDocument.write_docx (added in rtflite 2.2.0) creates DOCX files for individual rtflite tables directly. Use concatenate_docx (added in rtflite 2.3.0, powered by python-docx) to concatenate the DOCX outputs when you need final files without manual field refreshes, similar to assemble_rtf.

Generate example DOCX tables:

from importlib.resources import files

import polars as pl
import rtflite as rtf

ae_path = files("rtflite.data").joinpath("adae.parquet")
ae = pl.read_parquet(ae_path)
ae_summary = (
    ae.group_by(["TRTA", "AEDECOD"])
    .agg(pl.len().alias("n"))
    .pivot(values="n", index="AEDECOD", on="TRTA")
    .fill_null(0)
    .sort("AEDECOD")
)

# Two portrait tables
portrait_doc1 = rtf.RTFDocument(
    df=ae_summary.head(12),
    rtf_title=rtf.RTFTitle(text="Adverse Events (Portrait)"),
    rtf_column_header=rtf.RTFColumnHeader(
        text=[
            "Adverse Events",
            "Placebo (N=86)",
            "Xanomeline High Dose (N=84)",
            "Xanomeline Low Dose (N=84)",
        ],
    ),
    rtf_body=rtf.RTFBody(col_rel_width=[4, 2, 2, 2]),
)
portrait_doc1.write_docx("portrait-ae-1.docx")

portrait_doc2 = rtf.RTFDocument(
    df=ae_summary.slice(12, 12),
    rtf_title=rtf.RTFTitle(text="Adverse Events (Portrait, Part 2)"),
    rtf_column_header=rtf.RTFColumnHeader(
        text=[
            "Adverse Events",
            "Placebo (N=86)",
            "Xanomeline High Dose (N=84)",
            "Xanomeline Low Dose (N=84)",
        ],
    ),
    rtf_body=rtf.RTFBody(col_rel_width=[4, 2, 2, 2]),
)
portrait_doc2.write_docx("portrait-ae-2.docx")

# One landscape table
landscape_doc = rtf.RTFDocument(
    df=ae_summary.head(20),
    rtf_page=rtf.RTFPage(
        orientation="landscape",
        nrow=10,
        border_first="dashed",
        border_last="dashed",
    ),
    rtf_title=rtf.RTFTitle(text="Adverse Events Summary - Landscape Layout"),
    rtf_column_header=rtf.RTFColumnHeader(
        text=[
            "Adverse Events",
            "Placebo (N=86)",
            "Xanomeline High Dose (N=84)",
            "Xanomeline Low Dose (N=84)",
        ],
    ),
    rtf_body=rtf.RTFBody(col_rel_width=[4, 2, 2, 2]),
)
landscape_doc.write_docx("landscape-ae.docx")

Concatenate two portrait DOCX files

Use concatenate_docx to start from the first DOCX (avoids a blank leading page) and add a new section per file so each starts on its own page with the correct orientation.

portrait_files = [
    "portrait-ae-1.docx",
    "portrait-ae-2.docx",
]

concatenate_docx(
    portrait_files,
    "combined-python-docx.docx",
)

Concatenate portrait + landscape DOCX files

files_with_orientation = [
    ("portrait-ae-1.docx", False),
    ("landscape-ae.docx", True),
]

concatenate_docx(
    [path for path, _ in files_with_orientation],
    "combined-python-docx-mixed.docx",
    landscape=[is_landscape for _, is_landscape in files_with_orientation],
)