Pandas - 单元格中的最大值并保存与其对应的行 [英] Pandas - max value in a cell and save rows corresponded to it

问题描述

我有这个问题，我想在每个段中找到最高值.每个段都表示时间，因此所有行都对应于时间，正如您所看到的大部分时间步长是五分钟，对于每个步骤，我需要在第 4 列中找到最大值，在此期间我需要保存整行.到目前为止，我想出了这个:

I have this problem, where I want to find a highest value in each segment. Each segment means time, so all the rows corresponding to time, as you can see most of time step is five minute and for each step I need to find highest value in the 4th column, during that I need to save the whole row. So far I came up with this:

import pandas as pd
import numpy as np

data = pd.read_csv(f'/home/20170116.csv', header=None, sep=';',
                   usecols=[0, 1, 2, 3, 4, 5], names=['Time', 'degree', 'f1', 'p1', 'Intensity', 'Distance'])

for i in range(1, 5473, 19):
    print(data.iloc[:i])

我的数据如下所示:

00:00   0   7.44077320746235    0.453540438929378   317900000   67
00:00   10  7.39076196898179    0.487011284672025   341400000   67
00:00   20  7.37075747358957    0.506065836725554   328000000   65
00:00   30  7.34075073050124    0.495374317737197   321000000   65
00:00   40  7.33074848280513    0.473928991378983   379500000   70
00:00   50  7.33074848280513    0.429714866376765   344100000   70
00:00   60  7.34075073050124    0.378940997444553   461400000   77
00:00   70  7.37075747358957    0.330831053566623   402800000   77
00:00   80  7.43077095976624    0.28999520431443    353100000   77
00:00   90  7.50078669363902    0.256630783010184   312400000   77
00:00   -90 7.51078894133513    0.257848411262383   114700000   52
00:00   -80 7.59080692290402    0.226286016578661   92620000    48
00:00   -70 7.71083389525736    0.199411631799538   81620000    48
00:00   -60 7.81085637221848    0.178324045166602   217100000   77
00:00   -50 7.87086985839514    0.17447741754611    212400000   77
00:00   -40 7.8308608676107     0.209620778938056   276100000   78
00:00   -30 7.73083839064958    0.272603273214342   359100000   78
00:00   -20 7.61081141829625    0.341747195487005   361600000   75
00:00   -10 7.51078894133513    0.401902182098869   260500000   65

所以上面的一个段显示时间每 5 分钟增加一次，所以我有 288 个段，每个段有 19 行.我需要在第 4 列 p1 中找到最大值并将整行保存到另一个文件中.

So above one segment is presented time increases every 5 minutes so I have 288 segments and each has 19 rows. And I need to find max value in the 4th column p1 and save the whole row to another file for example.

推荐答案

是否有效:

df.loc[df.groupby('Time')['p1'].idxmax()]

输出:

    Time  degree        f1        p1  Intensity  Distance
1  00:00      20  7.370757  0.506066  328000000        65

这篇关于Pandas - 单元格中的最大值并保存与其对应的行的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！