Objective
I have a dataset, df, that I would like to group the length column, take its sum, and display the endtime that's associated with it:
length start end duration
6330 12/17/2019 10:34:23 AM 12/17/2019 10:34:31 AM 8
57770 12/19/2019 5:19:56 PM 12/17/2019 5:24:19 PM 263
6330 12/17/2019 10:34:54 AM 12/17/2019 10:35:00 AM 6
6330 12/18/2019 4:36:44 PM 12/18/2019 4:37:13 PM 29
57770 12/19/2019 5:24:47 PM 12/19/2019 5:26:44 PM 117
Desired Output
length end total Duration
6330 12/18/2019 4:37:13 PM 43
57770 12/19/2019 5:26:44 PM 380
Dput
structure(list(length = c(6330L, 57770L, 6330L, 6330L, 57770L
), start = structure(c(1L, 4L, 2L, 3L, 5L), .Label = c("12/17/2019 10:34:23 AM",
"12/17/2019 10:34:54 AM", "12/18/2019 4:36:44 PM", "12/19/2019 5:19:56 PM",
"12/19/2019 5:24:47 PM"), class = "factor"), end = structure(c(1L,
3L, 2L, 4L, 5L), .Label = c("12/17/2019 10:34:31 AM", "12/17/2019 10:35:00 AM",
"12/17/2019 5:24:19 PM", "12/18/2019 4:37:13 PM", "12/19/2019 5:26:44 PM"
), class = "factor"), duration = c(8L, 263L, 6L, 29L, 117L)), class = "data.frame", row.names = c(NA,
-5L))
This is what I have tried:, but how do I also display the end column that's associated with the 'latest' length value? For instance, length, 6330 has 3 end values, with 3 durations attached to it:
12/17/2019 10:34:31 AM 8
12/17/2019 10:35:00 AM 6
12/18/2019 4:37:13 PM 29
12/18/2019 4:37:13 PM is the latest end time, so I would like to output the end time,
along with the sum of durations for this particular length value.
Desired Output
length end total Duration
6330 12/18/2019 4:37:13 PM 43
57770 12/19/2019 5:26:44 PM 380
This is what I have tried:
import pandas as pd
import numpy as np
df1 = df.groupby('length')['duration'].sum()
However, it only outputs the length and total duration. How would I output the length, the latest end as well as the total duration for that particular length?
Any help is appreciated.
In R
, we can group by 'length', use summarise
and get the sum
of 'duration' and extract the max
element of 'end' after converting to DateTime class with mdy_hms
(from lubridate
)
library(dplyr)
library(lubridate)
df %>%
group_by(length) %>%
summarise(duration = sum(duration), end = end[which.max(mdy_hms(end))])
Pandas we can use GroupBy.agg
for this, but we have two choices here:
df.groupby('length').agg({'duration': 'sum', 'end': 'max'}).reset_index()
length duration end
0 6330 43 2019-12-18 16:37:13
1 57770 380 2019-12-19 17:26:44
new since pandas 0.25.0+
df.groupby('length').agg(
end=('end', 'max'),
total_duration=('duration', 'sum')
).reset_index()
length end total_duration
0 6330 2019-12-18 16:37:13 43
1 57770 2019-12-19 17:26:44 380
Note: dont forget to convert your date columns to datetime before:
df[['start', 'end']] = (
df[['start', 'end']].apply(lambda x: pd.to_datetime(x, infer_datetime_format=True))
)
In R, it can be done using some tidyverse
libraries:
library(tidyverse)
df <- tribble(
~length,~start,~end,~duration,
6330,"12/17/2019 10:34:23 AM","12/17/2019 10:34:31 AM",8,
57770,"12/19/2019 5:19:56 PM","12/17/2019 5:24:19 PM",263,
6330,"12/17/2019 10:34:54 AM","12/17/2019 10:35:00 AM",6,
6330,"12/18/2019 4:36:44 PM","12/18/2019 4:37:13 PM",29,
57770,"12/19/2019 5:24:47 PM","12/19/2019 5:26:44 PM",117
) %>%
mutate_at(
vars(start, end),
lubridate::mdy_hms
)
df %>%
group_by(length) %>%
summarise(
end = max(end, na.rm = TRUE),
duration = sum(duration, na.rm = TRUE)
)
Giving:
# A tibble: 2 x 3
length end duration
<dbl> <dttm> <dbl>
1 6330 2019-12-18 16:37:13 43
2 57770 2019-12-19 17:26:44 380
Timestamps are formatted in ISO format.
I have used the default TZ (UTC) when converting the values.
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