Extract date text from string

Question

I would like to extract date from the following list of text:

[[1]]
[1] \"TAX INVOICE      28 Dec 2018       PO2222\"

[[2]]
[1] \"TAX INVOICE      20 Nov 2018          


        

Answer 1

Here is a base R option using lapply and gsub:

lst <- list("TAX INVOICE      28 Dec 2018       PO2222",
            "TAX INVOICE      20 Nov 2018       PO11111")

lapply(lst, function(x) gsub(".*(\\d{2} \\w{3} \\d{4}).*", "\\1", x))
[[1]]
[1] "28 Dec 2018"

[[2]]
[1] "20 Nov 2018"

Demo