How to optimize the code to reduce computational time

I would very much like to optimize the code below. I used the tictoc function to calculate the calculation time, the time is even short (0.17 sec elapsed), but I would like to know if there is a way to make it even faster. I made an explanation in some parts of the code. I see that I leave a lot of code line by line, instead of using %>%, but I don't know that would also reduce computational time.

One idea would be to know which command is taking the longest to execute and thus adjust.

library(dplyr)
library(tidyverse)
library(lubridate)
library(tictoc)

df1 <- structure(
  list(
    Id = c(
      4,
      4,
      4,
      4,
      4,
      4,
      4,
      4,
      4,
      4,
      4,
      4,
      4,
      4,
      4,
      4,
      1011,
      1011,
      1011,
      1011,
      1011,
      1011,
      1011,
      1011,
      1011
    ),
    Tp = c(
      1,
      1,
      1,
      1,
      1,
      0,
      1,
      1,
      1,
      1,
      0,
      1,
      1,
      1,
      1,
      1,
      NA,
      NA,
      NA,
      NA,
      NA,
      NA,
      NA,
      NA,
      NA
    ),
    date1 = structure(
      c(
        1641945600,
        1641945600,
        1641945600,
        1641945600,
        1641945600,
        1641945600,
        1641945600,
        1641945600,
        1641945600,
        1641945600,
        1641945600,
        1641945600,
        1641945600,
        1641945600,
        1641945600,
        1641945600,
        1641945600,
        1641945600,
        1641945600,
        1641945600,
        1641945600,
        1641945600,
        1641945600,
        1641945600,
        1641945600
      ),
      class = c("POSIXct",
                "POSIXt"),
      tzone = "UTC"
    ),
    date2 = structure(
      c(
        1641340800,
        1641340800,
        1641427200,
        1641427200,
        1641513600,
        1641513600,
        1641600000,
        1641600000,
        1641686400,
        1641686400,
        1641772800,
        1641772800,
        1641859200,
        1641859200,
        1641945600,
        1641945600,
        1641254400,
        1641340800,
        1641427200,
        1641513600,
        1641600000,
        1641686400,
        1641772800,
        1641859200,
        1641945600
      ),
      class = c("POSIXct", "POSIXt"),
      tzone = "UTC"
    ),
    Week = c(
      "Wednesday",
      "Wednesday",
      "Thursday",
      "Thursday",
      "Friday",
      "Friday",
      "Saturday",
      "Saturday",
      "Sunday",
      "Sunday",
      "Monday",
      "Monday",
      "Tuesday",
      "Tuesday",
      "Wednesday",
      "Wednesday",
      "Tuesday",
      "Wednesday",
      "Thursday",
      "Friday",
      "Saturday",
      "Sunday",
      "Monday",
      "Tuesday",
      "Wednesday"
    ),
    Category = c(
      "ABC",
      "EFG",
      "ABC",
      "EFG",
      "ABC",
      "EFG",
      "ABC",
      "EFG",
      "ABC",
      "EFG",
      "ABC",
      "EFG",
      "ABC",
      "EFG",
      "ABC",
      "EFG",
      "ABC",
      "ABC",
      "ABC",
      "ABC",
      "ABC",
      "ABC",
      "ABC",
      "ABC",
      "ABC"
    ),
    DR1 = c(
      0,
      0,
      0,
      0,
      0,
      0,
      0,
      0,
      0,
      0,
      0,
      0,
      0,
      NA,
      NA,
      0,
      200,
      350,
      330,
      400,
      400,
      332,
      327.9,
      383.6,
      0
    ),
    DRM0 = c(
      300,
      300,
      300,
      300,
      300,
      300,
      300,
      300,
      300,
      300,
      300,
      300,
      300,
      300,
      0,
      0,
      200,
      350,
      330,
      400,
      400,
      332,
      327.9,
      327.6,
      323.75
    ),
    DRM01 = c(
      300,
      300,
      300,
      300,
      300,
      300,
      300,
      300,
      300,
      300,
      300,
      300,
      300,
      300,
      0,
      0,
      200,
      350,
      330,
      400,
      400,
      332,
      327.9,
      340,
      329.17
    ),
    DRM02 = c(
      300,
      300,
      300,
      300,
      300,
      300,
      300,
      300,
      300,
      300,
      300,
      300,
      300,
      300,
      300,
      0,
      200,
      350,
      330,
      400,
      400,
      332,
      340,
      340,
      329.17
    ),
    DRM03 = c(
      300,
      300,
      300,
      300,
      300,
      300,
      300,
      300,
      300,
      300,
      300,
      300,
      300,
      300,
      300,
      0,
      200,
      350,
      330,
      400,
      400,
      338.8,
      340,
      340,
      329.17
    ),
    DRM04 = c(
      300,
      250,
      250,
      250,
      250,
      250,
      250,
      250,
      250,
      250,
      300,
      300,
      300,
      300,
      300,
      0,
      200,
      350,
      330,
      400,
      400,
      338.8,
      340,
      340,
     NA
    )
  ),
  row.names = c(NA,-25L),
  class = c("tbl_df",
            "tbl", "data.frame")
)

tic()

idd<-"4"
dmda<-"2022-01-12"
CategoryChosse<-"ABC"

df1$Week <- weekdays(df1$date2) #changing weekday names from Week column according to dates from date2

df1$Tp[is.na(df1$Tp)] <- 0 # IF you have NA in the TP column, use 0.

selection = startsWith(names(df1), "DR")

df1[selection][is.na(df1[selection])] = 0 # IF you have NA in the DRs columns, use 0.

df2<-subset(df1,df1$date2<df1$date1) # The idea here is to use dates smaller than the value of date1 to calculate the median after (historical data)

x<-df2 %>% select(starts_with("DRM0"))

x<-cbind(df2, setNames(df2$DR1 - x, paste0(names(x), "_PV")))

PV<-select(x,Id, date2,Week, Category, DR1, ends_with("PV"))

med<-PV %>%
  group_by(Id,Category,Week) %>%
  dplyr::summarize(dplyr::across(ends_with("PV"), median))

SPV<-df1%>% #
  inner_join(med, by = c('Id','Category', 'Week')) %>%
  mutate(across(matches("^DRM0\\d+$"), ~.x + 
                  get(paste0(cur_column(), '_PV')),
                .names = '{col}_{col}_PV')) %>%
  select(Id:Category, DRM01_DRM01_PV:last_col())

SPV<-data.frame(SPV)

SPV <- SPV %>% #Here I specifically filter the id, category and date I want from SPV
  filter(Id==idd,date2 == ymd(dmda), Category == CategoryChosse) 

toc()

Hi JojoSouza,

though I'm not going to go through your code, because what you do seems rather specific. I want to answer to you last part.

One idea would be to know which command is taking the longest to execute and thus adjust.

Here, you can use the "Profile" function in RStudio, which is build on the package with the same name. Simply select the lines you want to analyze and choose in the menu "profiling"->"Profile selected lines". You will get a result with time elapsed and memory approximations for each line of code. Because your code already runs very fast, this wont give you usable information, however. Wrap your code in a for loop to run it 100 times or so and profile the complete loop instead. Usually this helps getting useful information out of fast code. You can then try out microbenchmark to test equivalent, but perhaps faster code (You can set a "times" argument, for how often the code should be run.
However, I would only go through that trouble if the above code is eventually run hundreds of time (Or of course just for the fun of it :wink: ).
I hope this helps.
Best,
Valentin