PythonでExcel自動化！openpyxl入門ガイド【2025年最新版】

pip install openpyxl

import openpyxl
print(openpyxl.__version__) # → 3.1.5

from openpyxl import Workbook

wb = Workbook() # 新規ブックを生成
ws = wb.active # アクティブシート取得
ws["A1"] = "Hello openpyxl!"# セル書き込み
wb.save("hello.xlsx") # ファイル保存
print("Excelを自動生成しました ✅")

from openpyxl import load_workbook

wb = load_workbook("hello.xlsx")
ws = wb.active
print(ws["A1"].value)            # → Hello openpyxl!

ws["B1"] = "=SUM(1, 2, 3)"       # 数式もそのまま書き込める
wb.save("hello_edited.xlsx")

template = load_workbook("invoice_template.xlsx")
ws = template["請求書"]
ws["D4"] = "株式会社サンプル"
ws["D5"] = "2025/07/31"
for i, (name, qty, price) in enumerate(items, start=8):
    ws[f"A{i}"] = name
    ws[f"D{i}"] = qty
    ws[f"E{i}"] = price
template.save("invoice_202507.xlsx")

import csv, glob
from openpyxl import Workbook
wb = Workbook()
for csv_path in glob.glob("*.csv"):
    ws = wb.create_sheet(title=csv_path[:-4])
    with open(csv_path, newline="") as f:
        for row in csv.reader(f):
            ws.append(row)
wb.remove(wb["Sheet"])           # 既定シートを削除
wb.save("merged.xlsx")

from openpyxl.chart import BarChart, Reference
wb = load_workbook("sales_data.xlsx")
ws = wb.active

chart = BarChart()
chart.title = "月別売上"
data = Reference(ws, min_col=2, max_col=2, min_row=1, max_row=13)
cats = Reference(ws, min_col=1, max_col=1, min_row=2, max_row=13)
chart.add_data(data, titles_from_data=True)
chart.set_categories(cats)
ws.add_chart(chart, "D2")

wb.save("sales_report.xlsx")

from openpyxl.styles import Font, PatternFill, Alignment, Border, Side

ws["A1"].font = Font(bold=True, color="FFFFFF", size=14)
ws["A1"].fill = PatternFill("solid", fgColor="4F81BD")
ws["A1"].alignment = Alignment(horizontal="center", vertical="center")

thin = Side(border_style="thin", color="000000")
ws["A1"].border = Border(top=thin, left=thin, right=thin, bottom=thin)