python csv，仅一次写入标头

python csv，仅一次写入标头

您可以检查文件是否已经存在，然后不调用，

writeheader()

因为您使用附加选项打开文件。

像这样：

import os.pathfile_exists = os.path.isfile(filename)with open (filename, 'a') as csvfile:    headers = ['TimeStamp', 'light', 'Proximity']    writer = csv.DictWriter(csvfile, delimiter=',', lineterminator='n',fieldnames=headers)    if not file_exists:        writer.writeheader()  # file doesn't exist yet, write a header    writer.writerow({'TimeStamp': dic['ts'], 'light': dic['light'], 'Proximity': dic['prox']})