いつも忘れて検索し直すのでメモ
csvファイルをlist形式で読み込む
with open('filename.csv', 'r') as f:
reader = csv.reader(f)
lines = [row for row in reader]
listをcsvファイル形式で書き出す
lines = [['身長', '体重', '名前'], [129.3, 129.3, 'ドラえもん']]
with open('filename.csv', 'w') as f:
writer = csv.writer(f)
writer.writerows(lines)