如何在python熊猫中将日期时间转换为毫秒

Question

So I want to convert the datetime to millisecond my code is here

import pandas as pd
import numpy as np
flyer = pd.read_csv("./csv/Flyers Dataset - Flyers Dataset.csv",parse_dates = ['timestamp'])

flyer.dropna(axis=0, how='any', thresh=None, subset=None, inplace=True)

pd.set_option('display.max_rows', 20)

flyer.to_csv('myfile.csv')

so the flyer variable is basically my entire dataframe(it's my csv file). The csv https://i.stack.imgur.com/qLq2U.png

any sort of feedback will be greatly appreciated. I am sorry about any of the formatting on this question this is only my second one.

Sincerely,

Gratefull StackOverflow User

Answer 1

Given that the 'timestamp' column is a datetime object, and your base reference date is October 1 2018, here's how you can compute the timedelta in milliseconds

import pandas as pd
from datetime import datetime, timedelta, timezone

Firstly, get the timezone info from your sample timestamp input:

datetime.strptime('2018-10-01 13:56:36-0400', '%Y-%m-%d %H:%M:%S%z')
>>>datetime.datetime(2018, 10, 1, 13, 56, 36, tzinfo=datetime.timezone(datetime.timedelta(-1, 72000)))

Then we can create a tz-aware base date with the same timezone details. You should be able to do the subtraction after that.

base_date = datetime(2018,10,1, tzinfo=timezone(timedelta(-1,72000)))

flyer = pd.read_csv("./csv/Flyers Dataset - Flyers Dataset.csv",parse_dates = ['timestamp'])
flyer.dropna(axis=0, how='any', thresh=None, subset=None, inplace=True)

# 1000 milliseconds in a second
flyer.loc[:,'TimeDelta'] = flyer.loc[:,'timestamp'].apply(lambda x: (x - base_date).total_seconds() * 1000)

pd.set_option('display.max_rows', 20)

flyer.to_csv('myfile.csv')