You can use the following syntax to calculate a difference between two times in a pandas DataFrame:
#calculate time difference in hours df['hours_diff'] = (df.end_time - df.start_time) / pd.Timedelta(hours=1) #calculate time difference in minutes df['min_diff'] = (df.end_time - df.start_time) / pd.Timedelta(minutes=1) #calculate time difference in seconds df['sec_diff'] = (df.end_time - df.start_time) / pd.Timedelta(seconds=1)
This particular example calculates the difference between the times in the end_time and start_time columns of some pandas DataFrame.
The following example shows how to use this syntax in practice.
Example: Calculate Difference Between Two Times in Pandas
Suppose we have the following pandas DataFrame:
import pandas as pd #create DataFrame df=pd.DataFrame({'start_time':pd.date_range(start='5/25/2020',periods=6,freq='15min'), 'end_time':pd.date_range(start='5/26/2020',periods=6,freq='30min')}) #view DataFrame print(df) start_time end_time 0 2020-05-25 00:00:00 2020-05-26 00:00:00 1 2020-05-25 00:15:00 2020-05-26 00:30:00 2 2020-05-25 00:30:00 2020-05-26 01:00:00 3 2020-05-25 00:45:00 2020-05-26 01:30:00 4 2020-05-25 01:00:00 2020-05-26 02:00:00 5 2020-05-25 01:15:00 2020-05-26 02:30:00
We can use the following syntax to calculate the time difference between the start_time and end_time columns in terms of hours, minutes, and seconds:
#calculate time difference in hours df['hours_diff'] = (df.end_time - df.start_time) / pd.Timedelta(hours=1) #calculate time difference in minutes df['min_diff'] = (df.end_time - df.start_time) / pd.Timedelta(minutes=1) #calculate time difference in seconds df['sec_diff'] = (df.end_time - df.start_time) / pd.Timedelta(seconds=1) #view updated DataFrame print(df) start_time end_time hours_diff min_diff sec_diff 0 2020-05-25 00:00:00 2020-05-26 00:00:00 24.00 1440.0 86400.0 1 2020-05-25 00:15:00 2020-05-26 00:30:00 24.25 1455.0 87300.0 2 2020-05-25 00:30:00 2020-05-26 01:00:00 24.50 1470.0 88200.0 3 2020-05-25 00:45:00 2020-05-26 01:30:00 24.75 1485.0 89100.0 4 2020-05-25 01:00:00 2020-05-26 02:00:00 25.00 1500.0 90000.0 5 2020-05-25 01:15:00 2020-05-26 02:30:00 25.25 1515.0 90900.0
The new columns contain the time differences between the start_time and end_time columns in various units.
For example, consider the first row:
- The difference between the start time and end time is 24 hours.
- The difference between the start time and end time is 1,440 minutes.
- The difference between the start time and end time is 86,400 seconds.
Note that in this example, the start_time and end_time columns are already formatted as datetimes.
If your time columns are instead currently formatted as strings, you can use pd.to_datetime to first convert each column to a datetime format before calculating the difference between the times:
#convert columns to datetime format
df[['start_time', 'end_time']] = df[['start_time', 'end_time]].apply(pd.to_datetime)
You can then proceed to calculate the time differences between the columns since they are both now in a datetime format that pandas can recognize.
Additional Resources
The following tutorials explain how to perform other common operations in pandas:
How to Create a Date Range in Pandas
How to Extract Month from Date in Pandas
How to Convert Timestamp to Datetime in Pandas