François Michonneau <[log in to unmask]> 3:43 PM (4 minutes ago) to UF Hi Nihal Here is a possible solution ``` library(tidyverse) library(readxl) dt <- read_excel("example_for_R_listerv.xlsx", skip = 1) %>% mutate(date = format(time, "%Y-%m-%d")) ``` If your dates are already properly formatted, you don't have to use regular expressions. The functions that read data in the tidyverse detect automatically that it's a date and parse them as such. Once your data is in the date format, you can use the "format" function to extract the year (%Y), month (%m) and day (%d) in a new column here named "date". However, depending on what you are trying to accomplish with your data you may not have to do that. For instance, you can filter for a time period directly on your initial column without having to extract the exact day. Also note that I put "skip = 1" and the column headers are actually not in your first row of the spreadsheet (which might be why the "time" column was not recognized in the code example you sent). I hope this helps. Best -- François On Fri, Jul 27, 2018 at 3:31 PM El Rouby,Nihal M <[log in to unmask]> wrote: > Dear All- > > > > Trying to extract dates from a variable in a data frame and then make a > new column with these dates. I’m using regular expression along str_extract > command from package stringr. > > > > I’m getting the error “Error in geno_time$time : $ operator is invalid > for atomic vectors” when I used this command below on my dataframe. > > > > geno_time<-str_extract(geno_time$time,"[0-9]+\\/[0-9]+\\/[0-9]+[:blank:]?") > > > > I’m attaching example of my data and what I want to accomplish. > > > > I appreciate your input and have a great weekend. > > > > Best, > > Nihal > This list strives to be beginner friendly. However, we still ask that you > PLEASE do read the posting guide > https://urldefense.proofpoint.com/v2/url?u=http-3A__www.R-2Dproject.org_posting-2Dguide.html&d=DwIFaQ&c=pZJPUDQ3SB9JplYbifm4nt2lEVG5pWx2KikqINpWlZM&r=QWxQId63qB2iSP1ggUL7kQsdfEWUTu6qCGEw8Xuo91A&m=1gxtMVlwUy1KieIIAZ2D3z9XGGtD9blndoZwqdPs73o&s=YNlMgsazQduCXywYwompcIbfwGIRLF4Rtq3BQ8cVz28&e= and provide commented, > minimal, self-contained, reproducible code. > This list strives to be beginner friendly. However, we still ask that you PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.