方法一：strftime('%H:%M:%S',gmtime(x)))

例：

from time import gmtime
from time import strftime
import pandas as pd
import datetime
from datetime import timedelta

df=pd.read_excel(r'E:\数据源.xlsx')
df=df[~df['审核时间'].isnull()]

df['审核时间']=pd.to_datetime(df['审核时间'])
df['采样时间']=pd.to_datetime(df['采样时间'])

df['时长']=df['审核时间']-df['采样时间']

df['时长']=df['时长'].apply(lambda x:timedelta.total_seconds(x))
df['时长'].map(lambda x:strftime('%H:%M:%S',gmtime(x)))

Output:

以上方法中是先将timedelta转换为秒，然后再利用map(lambda x: strftime('%H:%M:%S',gmtime(x)))将秒转换为时分秒格式

timedelta转换为秒然用到函数：timedelta.total_seconds()

timedelta.total_seconds()：此方法的返回类型是一个数字，该数字是该时间段内覆盖的总秒数;

from datetime import time, timedelta  
    
## total_seconds function
x = timedelta(minutes = 2*15)
total = x.total_seconds()
print("Total seconds in 30 minutes:", total)

Output:    
Total seconds in 30 minutes: 1800.0

方法二：自定义一个函数

def convert(x):
    hours = x.components.hours
    minutes = x.components.minutes
    seconds = x.components.seconds
    return f"{hours}:{minutes}:{seconds}"
df['时长']=df['时长'].apply(convert)
df['时长'].head()

Output:

方法二中，Series.dt.components：返回 Timedeltas 组件的 Dataframe。

s = pd.Series(pd.to_timedelta(np.arange(5), unit='s'))
s
0   0 days 00:00:00
1   0 days 00:00:01
2   0 days 00:00:02
3   0 days 00:00:03
4   0 days 00:00:04
dtype: timedelta64[ns]
s.dt.components
   days  hours  minutes  seconds  milliseconds  microseconds  nanoseconds
0     0      0        0        0             0             0            0
1     0      0        0        1             0             0            0
2     0      0        0        2             0             0            0
3     0      0        0        3             0             0            0
4     0      0        0        4             0             0            0