About my GIS question in R (from readShapePoly to sf::st_read) - r

Question

I am needed to use sf package command, because readShapePoly commnad will be erased. That's neer future I know... So I want to change my code from route
thata readShapePloy to route sf::st_read. But I cannot write correct code. So I want to correct code and I am very happy, if u show correct sf package command. My now command below, thx...(I am sorry to my poor English skill,Plz over come it...)
In R, I wrote code again and again for ex, on sf::st_read command. But that show error again and again...code below nd error message below too
usa_state <- readShapePoly("usa_state.shp", IDvar = "STATE_CODE")
That is ok, but I know to change that code neer future, cuz this command is erased in neer future. So Plz show me command thata route of sf package.I tried below code but I know this is not understandable in R.
usa_state = sf::st_read("usa_state.shp", layer = "STATE_CODE")
bad code...Plz shw me correct coding!Error occured now am I...
Error in CPL_read_ogr(dsn, layer, query, as.character(options), quiet, :
SQL execution failed, cannot open layer.
In addition: Warning message:
In CPL_read_ogr(dsn, layer, query, as.character(options), quiet, :
GDAL Error 1: SQL Expression Parsing Error: syntax error, unexpected
identifier, expecting SELECT or '('. Occurred around : "STATE_CODE"

Answer 1

You're almost there with usa_state = sf::st_read("usa_state.shp", layer = "STATE_CODE").
I'm guessing that STATE_CODE is a field in the usa_state.shp shapefile. You don't need to supply any field names to the st_read() function. Just use:
library(sf)
usa_state = st_read("usa_state.shp")
You'll need to make sure that the usa_state.shp file (and its associated files) are in your current working directory, or you'll need to use the full path:
usa_state = st_read("/path/to/usa_state.shp")
The sf package is well worth getting to know. It's made all of my spatial work in R much easier.