datetime - date difference in hours with python (excel data import) -

i need calculate hour difference between 2 dates (format: year-month-daythh:mm:ss potentially transform data format (format: year-month-day hh:mm:ss) huge excel file. efficient way in python? have tried use datatime/time object (typeerror: expected string or buffer), timestamp (valueerror) , dataframe (does not give hour result).

thank help!

excel file:

order_date             received_customer   column3  2000-10-06t13:00:58    2000-11-06t13:00:58    1 2000-10-21t15:40:15    2000-12-27t10:09:29    2 2000-10-23t10:09:29    2000-10-26t10:09:29    3 .....                  .... 

datatime/time object code (typeerror: expected string or buffer):

import pandas pd import time t  data=pd.read_excel('/path/file.xlsx')  s1 = (data,['order_date']) s2 = (data,['received_customer'])  s1time = t.strptime(s1, "%y:%m:%d:%h:%m:%s") s2time = t.strptime(s2, "%y:%m:%d:%h:%m:%s")  deltainhours = (t.mktime(s2time) - t.mktime(s1time))  print deltainhours, "hours" 

timestamp (valueerror) code:

import pandas pd import datetime dt  data=pd.read_excel('/path/file.xlsx')  df = pd.dataframe(data,columns=['order_date','received_customer']) df.to = [pd.timestamp('order_date')] df.fr = [pd.timestamp('received_customer')] (df.fr-df.to).astype('timedelta64[h]') 

dataframe (does not return desired result)

import pandas pd  data=pd.read_excel('/path/file.xlsx')  df = pd.dataframe(data,columns=['order_date','received_customer'])  df['order_date'] = pd.to_datetime(df['order_date']) df['received_customer'] = pd.to_datetime(df['received_customer'])  answer = df.dropna()['order_date'] - df.dropna()['received_customer']  answer.astype('timedelta64[h]')  print(answer)       out:      0   24 days 16:38:07     1    0 days 00:00:00     2   20 days 12:39:52     dtype: timedelta64[ns]      should smth. that:      0   592 hour     1   0   hour     2   492 hour 

is there way convert timedelta64[ns] hours answer.astype('timedelta64[h]') ?

for each of solutions mixed datatypes , methods. whereas not find time explicitly explain mistakes, yet want providing (probably non optimal) solution. built solution out of previous tries , combined knowledge other questions such as:

convert timedelta days, hours , minutes

get total number of hours pandas timedelta?

note used python 3. hope solution guides way. solution one:

import pandas pd datetime import  datetime import numpy np  d = pd.read_excel('c:\\users\\nrieble\\desktop\\check.xlsx',header=0)  start = [pd.to_datetime(e) e in data['order_date'] if len(str(e))>4] end = [pd.to_datetime(e) e in data['received_customer'] if len(str(e))>4]  delta = np.asarray(s2time)-np.asarray(s1time) deltainhours = [e/np.timedelta64(1, 'h') e in delta]  print (deltainhours, "hours")