检查一行中的日期是否早于下一行中的另一个日期

Question

我在 Python 中有以下代码：import pandas as pdimport numpy as npdate_rng = pd.date_range(start='5/18/2019', end='7/22/2020', freq='S')df = pd.DataFrame(date_rng, columns=['start_timestamp'])df['end_timestamp'] = date_rngdf['start_timestamp'] = np.random.randint(1589760000,1595376000,size=(len(date_rng)))df['end_timestamp'] = np.random.randint(1589760000,1595376000,size=(len(date_rng)))df = df[(df.end_timestamp/df.start_timestamp<=1.000009)&(df.end_timestamp/df.start_timestamp>=1.000001)]df = df.sort_values(by=['start_timestamp','end_timestamp'])df['start_timestamp'] = pd.to_datetime(df['start_timestamp'],unit='s')df['end_timestamp'] = pd.to_datetime(df['end_timestamp'],unit='s')结果，我有以下数据框：  start_timestamp     end_timestamp2020-05-18 00:00:30 2020-05-18 00:54:072020-05-18 00:01:40 2020-05-18 03:50:392020-05-18 00:02:08 2020-05-18 02:39:412020-05-18 00:04:01 2020-05-18 00:47:252020-05-18 00:04:01 2020-05-18 02:26:502020-05-18 00:04:44 2020-05-18 02:17:53                .                .                .我应该怎么做才能确保在我的数据集中每个end_timestamp都是在其下一行之前的日期时间start_timestamp？已实施的解决方案我基本上将数据集转换为数组，将其按升序排列并将其转换回数据框。它可能不是最优雅的解决方案，但它工作正常并为我打算使用的内容生成了一致的数据。import pandas as pdimport numpy as npdate_rng = pd.date_range(start='7/22/2019', end='7/22/2020', freq='S')df = pd.DataFrame(date_rng, columns=['start_timestamp'])df['end_timestamp'] = date_rngdf['start_timestamp'] = np.random.randint(1563753600,1595376000,size=(len(date_rng)))df['end_timestamp'] = np.random.randint(1563753600,1595376000,size=(len(date_rng)))df = df[(df.end_timestamp/df.start_timestamp<=1.0000009)&(df.end_timestamp/df.start_timestamp>=1.0000001)]df = df.to_numpy()df = df.reshape(df.shape[0]*2,1)df = np.sort(df,axis=0)df = df.reshape(int(df.shape[0]/2),2)df = pd.DataFrame(df,columns=['start_timestamp','end_timestamp'])df['start_timestamp'] = pd.to_datetime(df['start_timestamp'],unit='s')df['end_timestamp'] = pd.to_datetime(df['end_timestamp'],unit='s')

Answer 1

编写您的逻辑代码，一切都很好

1. freq='S'没有任何意义，您将生成与开始日期和结束日期之间的秒数一样多的行

2. 在随机化开始时间后，使用当前行和下一行作为结束时间随机函数的种子。这是作为列表理解吗

3. 在范围的开始和结束处获取 UTC 秒数时更聪明一些

import pandas as pd

import numpy as np

from datetime import datetime

# date_rng = pd.date_range(start='5/18/2019', end='7/22/2020', freq='S')

date_rng = pd.date_range(start='5/18/2019', end='5/19/2019', freq='min')

sec = [(date_rng.min() - datetime(1970, 1, 1)).total_seconds(),

       (date_rng.max() - datetime(1970, 1, 1)).total_seconds() ]

df = pd.DataFrame(date_rng, columns=['start_timestamp'])

df['start_timestamp'] = np.random.randint(sec[0],sec[1],size=(len(date_rng)))

df = df.sort_values(by="start_timestamp")

l = df["start_timestamp"].tolist()  # get randomised start times

l[-1] = sec[1] # set last time to end of range

# randomise end time between two start times

df['end_timestamp'] = [np.random.randint(l[i], l[i+1]) if i<len(l)-1  and l[i]<l[i+1] else l[i] for i, s in enumerate(l)]

df['start_timestamp'] = pd.to_datetime(df['start_timestamp'],unit='s')

df['end_timestamp'] = pd.to_datetime(df['end_timestamp'],unit='s')