How to edit cells Shapefile in R?

I downloaded a shapefile of the world map from gadm, however, there are typos that happen with importing the shape file. For example "Aland" shows up as "Ã…land" in the shapefile. There are handful of countries I want to make changes to.

world map shapefile, the one that says "You can also download this version as six separate layers (one for each level of subdivision/aggregation), as a geopackage database or as shapefiles" :https://gadm.org/download_world.html

I imported the shapefile using:

worldmap <- readOGR("file/gadm36_0.shp")

I tried using the following code:

levels(wordlmap$NAME_0)[5] <- "Aland"

However I got this message:

Error in `levels<-`(`*tmp*`, value = c(NA, NA, NA, NA, "Aland")) :
  factor level [2] is duplicated

Could you suggest how this code can be made better or an alternative.Thanks in advance

Solution

Since you did not provide a shapefile, I just worked with a publicly-available shapefile of Indian states. The long and short of it is to use the sf package. It loads shapefiles as (quasi) dataframes--with the longitudes and latitudes stored in the geometry variable. Then, you should be in familiar territory. Here is some code to change a state name variable:

# clear environment
rm(list=ls(all=TRUE))

# let's take admin 1 (states)
# note: already in WGS84 format
library(sf)
india_shape <- st_read("india_shape/gadm36_IND_1.shp", stringsAsFactors=FALSE)

# Let's pick something to change (state name)
> india_shape$NAME_1[1]
[1] "Andaman and Nicobar"

# Now change it
> india_shape$NAME_1[1] <- "New State Name"
> india_shape$NAME_1[1]
[1] "New State Name"