pythonでcsv dictを読み書きする方法

備忘録です．
辞書型配列の読込と書込です．
参考はこちら

CSVファイル読込の際には全ての値の型が保持されていないため，毎回データの型を指定する必要があることに注意．

import csv # module

def read_dict(file):
    with open(file, newline = "") as f:
        read_dict = csv.DictReader(f, delimiter=",", quotechar='"')
        ks = read_dict.fieldnames
        return_dict = {k: [] for k in ks}

        for row in read_dict:
            for k, v in row.items():
                return_dict[k].append(v) # notice the type of the value is always string.   

    return return_dict

def write_csv(file, save_dict):
    save_row = {}

    with open(file,'w') as f:
        writer = csv.DictWriter(f, fieldnames=save_dict.keys(),delimiter=",",quotechar='"')
        writer.writeheader()

        k1 = list(save_dict.keys())[0]
        length = len(save_dict[k1])

        for i in range(length):
            for k, vs in save_dict.items():
                save_row[k] = vs[i]

            writer.writerow(save_row)