Extract only the values that match a specific substring of a date in R

Question

Suppose I have a data set which looks as follows:

    V1  V2 V3    V4     V5   V6
    Tue Aug 10 10:04:09  0 2018
    Thu Aug 12 10:05:34  0 2018
    Wed Sep 15 09:25:56  0 2018
    Wed Sep 15 12:37:29  0 2018
    Mon Oct 17 04:21:18  0 2018
    Tue Oct 18 12:45:38  0 2018

Note that this data is in a .csv file and I want to extract the rows where the date is in the format Wed Sep 15 how to do this. Please clarify this issue as I'm new to R. Thanks!

Answer 1

Maybe the easiest way to do what you want, assuming that you want to do this on an ongoing basis, is to create a combined date column, then use that to filter. I will assume that your data frame is called df

library(dplyr)

df <- df %>%
    mutate(full_date = paste(V1,V2,V3))

#filter to your date
filt_date <- df %>%
    filter(full_date == 'Wed Sep 15')

If this is going to be a regular thing that you want to do, then you can also make a simple function, like this:

date_filter <- function(x,date) {

    y <- x %>%
        filter(full_date == date)

    return(y)
}

Then in the example above, you would do this:

filt_date <- df %>%
    date_filter('Wed Sep 15')