添加新行而不覆盖现有行

Question

I have a problem with writing dataframe to csv. So this is my code

sent_ts = int(request.headers['ts'])
recv_ts = int(round(time.time() * 1000))
call_ts = recv_ts - sent_ts

ts_list = {'sent_ts':[sent_ts], 'callback':[call_ts]}

df = pd.DataFrame(ts_list, columns = ['sent_ts', 'callback'])
df.to_csv('timestamp.csv', index = False)
print(df)

So when I executing the python script more than one times, it overwriting existing data not make a new row. How do I make a new row when every time I'm executed the python script? Thanks in advance !

Answer 1

Open the file in append mode, and write the new row to that file.

with open('timestamp.csv', 'a', newline = '') as f:
    df.to_csv(f, index = False, header = False)

header = False will prevent it from adding a header line each time you write a row.