How to **receive the EPSG code from a PROJ4 string using R**?

I have a bunch of raster datasets (randomly distributed all over the world, northern and southern hemisphere), with coordinate reference system UTM WGS84. Now I would like to find out the specific EPSG code for every dataset using R. Do you have any ideas?

```
# Install and load package raster
install.packages('raster')
library(raster)

# Load a specific raster dataset and query the crs
raster_dat <- raster('D:/UnknownUser/GlobalRasterData/raster_dat1')
crs(raster_dat)
# CRS arguments:
#  +proj=utm +zone=13 +datum=WGS84 +units=m +no_defs +ellps=WGS84 +towgs84=0,0,0

```

Maybe it is possible to create the EPSG code in a dynamic way, since it seems like the EPSG code is always a combination of <326> for the northern hemisphere and the specific zone number e.g. <32> (for Germany) which results in a EPSG code <326> + <32> = <32632>.

Unfortunately i figured out that it seems like you start with <327> for the southern hemisphere and add the specific zone number e.g. <32> (for Nigeria) which results in <327> + <32> =<32732>.

Now I am not sure whether this theory is correct (**verification needed incl. source please**) and if there is maybe an easier way to receive the EPSG code from the PROJ4 string.

Helpful links I have found:

URL:<https://spatialreference.org/ref/epsg/?page=9&search=wgs+84+utm>

URL:<https://epsg.io/32632>

URL:<https://de.wikipedia.org/wiki/UTM-Koordinatensystem#/media/Datei:Utm-zones.jpg>

**EDIT:**

```
# Install and load package rgdal
install.packages('rgdal')
library(rgdal)

# following function could be helpful; it creates a dataframe with 3columns; epsg-code, annotation and proj4-string - unfortunately it seems like there is not an epsg code for each utm wgs84 zone...
epsg_list <- rgdal::make_EPSG()

```

Thanks a lot in advance, ExploreR