Merging character "" with iterator i in a for loop

[Dam_So]

Hi,
I' m actually leaning R with RStudio, so I'm trying to do some function .
The problems is the following :
I'm trying to do a function which sort all the date in my dataset by month and print out the number of date for each month.
Here the function that i 'v tried :

GetNbAbsMonth <- function(varDate){
  for (i in 1:12)
  {
    month = grep(pattern = "/0"+i, x = varDate, value= TRUE)  //  get the date which contains "/01" then "/02"....  
    month[i] = count(mois) // stocking the number of each date for each month 
  }
}

But unsuccessfully.

I hope that I succed to make myself clear ( my english is shaky).
Thank for any help.

[pieterjanvc]

Hi,

Welcome to the RStudio community!

The code you have provided contains several errors. To start with, in R, comments are made by the # and not // . Also, trying to add an integer to a string "/0"+i is not possible like this. You have to use the paste function paste("/0"+i, sep = "").

I tried using your original function, but it's not clear what you are trying to do here and what the input / output looks like. However, I have made a small example in which I use various functions from the dplyr and lubridate package (part of the Tidyverse) to do what I think you want judging by the desctiption:

library(dplyr)
library(lubridate)

#Generate some data
set.seed(4) #Only needed for reproducibility 
myData = data.frame(
 date = as.character(Sys.Date() + sample(1:365, 10))
)
myData
#>          date
#> 1  2022-07-26
#> 2  2023-03-15
#> 3  2023-01-26
#> 4  2022-07-22
#> 5  2022-10-31
#> 6  2023-01-12
#> 7  2022-11-14
#> 8  2023-05-11
#> 9  2023-03-20
#> 10 2022-07-13


#Extact the month from each date, then sort by month, then day
myData = myData %>% 
 mutate( month = month(date), day = day(date)) %>% 
 arrange(month, day)

myData
#>          date month day
#> 1  2023-01-12     1  12
#> 2  2023-01-26     1  26
#> 3  2023-03-15     3  15
#> 4  2023-03-20     3  20
#> 5  2023-05-11     5  11
#> 6  2022-07-13     7  13
#> 7  2022-07-22     7  22
#> 8  2022-07-26     7  26
#> 9  2022-10-31    10  31
#> 10 2022-11-14    11  14

#Calculate the number of dates per month
myData %>% group_by(month) %>% summarise(n = n(), .groups = "drop")
#> # A tibble: 6 × 2
#>   month     n
#>   <dbl> <int>
#> 1     1     2
#> 2     3     2
#> 3     5     1
#> 4     7     3
#> 5    10     1
#> 6    11     1

^{Created on 2022-05-12 by the reprex package (v2.0.1)}

Should this be close to what you like to do, I suggest you look more into the dplyr verbs to get more familiar with them.

Hope this helps,
PJ