如何将DataFrame中的24小时制时间列转换为总秒数？

Hey there! Converting a HH:MM:SS time string column to total seconds in pandas is straightforward—here are a couple of clean, efficient ways to do it, using your sample data as a starting point.

First, let's complete your sample DataFrame code (since it was cut off) so we have a runnable example:

import pandas as pd
import random

def randomTime():
    rtime = int(random.random()*86400)
    hours = int(rtime/3600)
    minutes = int((rtime - hours*3600)/60)
    seconds = rtime - hours*3600 - minutes*60
    time_string = '%02d:%02d:%02d' % (hours, minutes, seconds)
    return time_string

time = [randomTime() for _ in range(8)]
events = ['ABC','DEF','GHI','JKL','ABC','DEF','GHI','JKL']  # Completed the Events list

df = pd.DataFrame({'Time': time, 'Events': events})
print(df)

Method 1: Use pd.to_timedelta (Simplest & Most Efficient) #

This is the go-to method—it directly converts your time string to a timedelta object, then we can grab the total seconds with total_seconds():

df['Total_Seconds'] = pd.to_timedelta(df['Time']).dt.total_seconds()
print(df)

Method 2: Manual Calculation (If You Want to Break It Down) #

If you prefer to see the individual components (hours, minutes, seconds) used in the calculation, here are two ways to do that:

Option A: Split the Time String

Split the HH:MM:SS string into separate columns, convert them to integers, then compute the total seconds:

# Split the Time column into hours, minutes, seconds
df[['Hours', 'Minutes', 'Seconds']] = df['Time'].str.split(':', expand=True).astype(int)

# Calculate total seconds
df['Total_Seconds'] = df['Hours'] * 3600 + df['Minutes'] * 60 + df['Seconds']

# Optional: Remove the intermediate columns if you don't need them
df = df.drop(['Hours', 'Minutes', 'Seconds'], axis=1)
print(df)

Option B: Use Datetime Conversion

Convert the time string to a datetime object (we can ignore the date part since we only care about time), then extract the hour, minute, and second values to compute total seconds:

# Convert Time to datetime format (using a dummy date under the hood)
df['Time_Datetime'] = pd.to_datetime(df['Time'], format='%H:%M:%S')

# Calculate total seconds from datetime components
df['Total_Seconds'] = df['Time_Datetime'].dt.hour * 3600 + df['Time_Datetime'].dt.minute * 60 + df['Time_Datetime'].dt.second

# Optional: Drop the datetime column
df = df.drop('Time_Datetime', axis=1)
print(df)

All these methods will give you the total number of seconds since midnight for each time entry. Method 1 is the most concise and performs best for large datasets.

内容的提问来源于stack exchange，提问作者user9394674