Python 从.dat文件中减去连续行

我希望从.dat文件中前面的行中减去行，然后从结果中生成一个新列。在我的文件中，我希望在第一列time中这样做，我希望找到每个timestep的时间间隔，然后从中创建一个新列。我从stackoverflow社区获得了帮助，并用python编写了一个伪代码。但到目前为止还不起作用：

import pandas as pd
import numpy as np
from sys import argv
from pylab import *
import csv

script, filename = argv

# read flash.dat to a list of lists
datContent = [i.strip().split() for i in open("./flash.dat").readlines()]

# write it as a new CSV file
with open("./flash.dat", "wb") as f:
    writer = csv.writer(f)
    writer.writerows(datContent)

columns_to_keep = ['#time']
dataframe = pd.read_csv("./flash.csv", usecols=columns_to_keep)

df = pd.DataFrame({"#time": pd.date_range("24 sept 2016"),periods=5*24,freq="1h")})
df["time"] = df["#time"]  + [pd.Timedelta(minutes=m) for m in np.random.choice(a=range(60), size=df.shape[0])]
df["value"] = np.random.normal(size=df.shape[0])

df["prev_time"] = [np.nan] + df.iloc[:-1]["time"].tolist()
df["time_delta"] = df.time - df.prev_time
df

dataframe.plot(x='#time', y='time_delta', style='r')
print dataframe
show()

为了您的方便，我也分享了这个文件，非常感谢您的帮助。

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我想你在找

df['time_diff']=df['time'].diff（）

@MaxU，你又是老板了！谢谢你，我想你在找的是df['time_diff']=df['time'].diff（）@MaxU，你又是老板了！谢谢