CODEWITHSUNDEEP
rfilter
Ben10
Ben10

Reputation: 297

Filter the lastest date in r

I wonder if there is a way to filter the lastest date of the factor and return the amount that match with it.

Here is my dataframe:

dat <- data.frame(
  time = factor(c("Breakfast","Breakfast","Breakfast","Breakfast","Breakfast","Breakfast"), levels=c("Breakfast")), date=c("2020-01-20","2020-01-21","2020-01-22","2020-02-10","2020-02-11","2020-02-12"),
  total_bill = c(12.7557,14.8,17.23,15.7,16.9,13.2)
)

We know that the lastest date is 2020-02-12 and I dont want to write the specific filter like filter(date %in% "2020-02-12") if the dataframe has been update a day after like 2020-02-13 It will be hard to filter with specific date.

Any help would be much appreciated. Thank you!

Upvotes: 1

Views: 119

Answers (3)

akrun
akrun

Reputation: 887108

An option with subset

subset(transform(dat, date = as.Date(date)), date == max(date))

Upvotes: 1

Conor
Conor

Reputation: 143

You can use lubridate::ymd to transform your date column from character to date, and then use filter and last to only select the row that contains the last date in the dataframe:

library(tidyverse)
library(lubridate)

dat %>%
  mutate(date = ymd(date)) %>%
  filter(date == last(date))

Upvotes: 2

JasonAizkalns
JasonAizkalns

Reputation: 20463

See ?which.max to get started:

dat <- data.frame(
  time = factor(c("Breakfast","Breakfast","Breakfast","Breakfast","Breakfast","Breakfast"), levels=c("Breakfast")), 
  date = c("2020-01-20","2020-01-21","2020-01-22","2020-02-10","2020-02-11","2020-02-12"),
  total_bill = c(12.7557, 14.8, 17.23, 15.7, 16.9, 13.2)
)

which.max(dat$date)
#> [1] 6

dat[which.max(dat$date), ]
#>        time       date total_bill
#> 6 Breakfast 2020-02-12       13.2

Alternatively, you can use dplyr:

library(dplyr)

dat %>%
  mutate(date = as.Date(date)) %>% 
  filter(date == max(date))
#>        time       date total_bill
#> 1 Breakfast 2020-02-12       13.2

Created on 2020-05-12 by the reprex package (v0.3.0)

Upvotes: 1

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