时间统计

import numpy as np
import pandas as pd
from datetime import datetime
from pandas.core.frame import DataFrame
import matplotlib.pyplot as plt
import time
import ast
import json

df = pd.read_excel('data.xlsx')
total_sec = []
total = []
total = pd.DataFrame(total)
num = 0
for index in range(0, 2707):
    row_data = df.loc[index, :]
    dt = "2055-01-01 01:01:01"
    dlt = datetime.strptime(dt, "%Y-%m-%d %H:%M:%S")
    start_time = row_data['start_time']
    if str(start_time)!='nan':
        start_time = datetime.strptime(start_time, "%Y-%m-%dT%H:%M:%S+08:00")
    else:
        start_time = dlt
    stop_time = row_data['stop_time']
    if str(stop_time)!='nan':
        stop_time = datetime.strptime(stop_time, "%Y-%m-%dT%H:%M:%S+08:00")
    else:
        stop_time = dlt

    if stop_time==dlt or start_time==dlt:
        total_sec.append(0)
    else:
        tot = (stop_time - start_time).seconds
        total_sec.append(tot)
total['作答时间']  = total_sec
total.to_excel('data_test.xlsx')