adejones/python-docx-replace-text-and-retain-style.py

## python-docx-replace-text-and-retain-style.py
def docx_replace(doc, data):
	paragraphs = list(doc.paragraphs)
	for t in doc.tables:
		for row in t.rows:
			for cell in row.cells:
				for paragraph in cell.paragraphs:
					paragraphs.append(paragraph)
	for p in paragraphs:
		for key, val in data.items():
			key_name = '${{{}}}'.format(key) # use placeholders in the form ${PlaceholderName}
			if key_name in p.text:
				inline = p.runs
				# Replace strings and retain the same style.
				# The text to be replaced can be split over several runs so
				# search through, identify which runs need to have text replaced
				# then replace the text in those identified
				started = False
				key_index = 0
				# found_runs is a list of (inline index, index of match, length of match)
				found_runs = list()
				found_all = False
				replace_done = False
				for i in range(len(inline)):

					# case 1: found in single run so short circuit the replace
					if key_name in inline[i].text and not started:
						found_runs.append((i, inline[i].text.find(key_name), len(key_name)))
						text = inline[i].text.replace(key_name, str(val))
						inline[i].text = text
						replace_done = True
						found_all = True
						break

					if key_name[key_index] not in inline[i].text and not started:
						# keep looking ...
						continue

					# case 2: search for partial text, find first run
					if key_name[key_index] in inline[i].text and inline[i].text[-1] in key_name and not started:
						# check sequence
						start_index = inline[i].text.find(key_name[key_index])
						check_length = len(inline[i].text)
						for text_index in range(start_index, check_length):
							if inline[i].text[text_index] != key_name[key_index]:
								# no match so must be false positive
								break
						if key_index == 0:
							started = True
						chars_found = check_length - start_index
						key_index += chars_found
						found_runs.append((i, start_index, chars_found))
						if key_index != len(key_name):
							continue
						else:
							# found all chars in key_name
							found_all = True
							break

					# case 2: search for partial text, find subsequent run
					if key_name[key_index] in inline[i].text and started and not found_all:
						# check sequence
						chars_found = 0
						check_length = len(inline[i].text)
						for text_index in range(0, check_length):
							if inline[i].text[text_index] == key_name[key_index]:
								key_index += 1
								chars_found += 1
							else:
								break
						# no match so must be end
						found_runs.append((i, 0, chars_found))
						if key_index == len(key_name):
							found_all = True
							break

				if found_all and not replace_done:
					for i, item in enumerate(found_runs):
						index, start, length = [t for t in item]
						if i == 0:
							text = inline[index].text.replace(inline[index].text[start:start + length], str(val))
							inline[index].text = text
						else:
							text = inline[index].text.replace(inline[index].text[start:start + length], '')
							inline[index].text = text
				# print(p.text)

# usage

doc = docx.Document('path/to/template.docx')
docx_replace(doc, dict(ItemOne='replacement text', ItemTwo="Some replacement text\nand some more")
doc.save('path/to/destination.docx')