dataframe将某列时间字符串转成时间

import datetime
import numpy as np

def func(x):
try:
return str(datetime.datetime.strptime(str(x)[:14], '%Y%m%d%H%M%S'))
except:
return np.NaN

df['交易时间戳'] = df['交易时间戳'].apply(lambda x: func(x))
print(df)