I would like to subset zips so I can get the files names (without the extension). For example, from zips[[1]] I want to get jan15-dec15cert_ext. Can somebody help me with this regular expression magic?
There are a number of approaches you can take. I wrote an RStudio addin that helps you preview regular expressions and outputs called regexplain that you might find helpful. It gives you interactive previews along the lines of the image below.
The fs package has a ton of functions for working with file paths and pulling out this info too, if you are into using pipes or if you are looking for help with discovering related functions:
library(fs)
library(tidyverse)
#> Warning: package 'tibble' was built under R version 3.5.2
#> Warning: package 'purrr' was built under R version 3.5.2
text <- "http://thedataweb.rm.census.gov/pub/cps/supps/jan15-dec15cert_ext.zip"
text %>%
path_file() %>%
path_ext_remove()
#> jan15-dec15cert_ext