leaflet:: Mapping wrong name of the countries - r

Question

I have a hard time to figure out why I can't map the right country on the map. I have gone through all of my codes, I still don't understand why is not working right.
If you see any problems, please let me know. I appreciate.
This is dataset
Country Total Code
1 China 34620 CHN
2 Japan 89 JPN
3 Singapore 40 SGP
4 Thailand 32 THA
5 Hong Kong 26 HKG
6 S. Korea 24 KOR
7 Taiwan 17 TWN
8 Malaysia 16 MYS
9 Australia 15 AUS
10 Germany 14 DEU
11 Vietnam 13 VNM
12 USA 12 USA
13 France 11 FRA
14 Macao 10 MAC
15 U.A.E. 7 ARE
16 Canada 7 CAN
17 Philippines 3 PHL
18 India 3 IND
19 Italy 3 ITA
20 U.K. 3 GBR
21 Russia 2 RUS
22 Finland 1 FIN
23 Sri Lanka 1 LKA
24 Sweden 1 SWE
25 Nepal 1 NPL
26 Cambodia 1 KHM
27 Spain 1 ESP
28 Belgium 1 BEL
library(leaflet)
library(maps)
library(maptools)
case <- read.csv("Cases_02072020_v1.csv",stringsAsFactors = FALSE)
Country = map("world", fill = TRUE, plot = FALSE, regions=iso.expand(case$Code,regex = TRUE))
IDs <- sapply(strsplit(Country$names, ":"), function(x) x[1])
Country <- map2SpatialPolygons(Country,
IDs=IDs,
proj4string=CRS("+proj=longlat +datum=WGS84"))
pal <- colorNumeric(
palette = "Blues",
domain = as.numeric(case$Total))
case$labels <- sprintf(
"<strong>Country:%s</strong><br/>Total:%g",
case$Country, case$Total)%>% lapply(htmltools::HTML)
leaflet(Country) %>% addTiles() %>%
addPolygons(fillOpacity = 0.6, smoothFactor = 0.5, stroke = TRUE, weight = 1,
color = pal(as.numeric(case$Total)),
label = case$labels)

Answer 1

You need to repeat each row of your case data frame so that the countries match each individual polygon on the map. This means ensuring you order them correctly and also you need to incorporate Macao and Hong Kong into China (or change the way you split IDs to handle them there).
Here is a full working version:
library(leaflet)
library(maps)
library(maptools)
case <- structure(list(Country = c("China", "Japan", "Singapore", "Thailand",
"Hong Kong", "S. Korea", "Taiwan", "Malaysia", "Australia", "Germany",
"Vietnam", "USA", "France", "Macao", "U.A.E.", "Canada", "Philippines",
"India", "Italy", "U.K.", "Russia", "Finland", "Sri Lanka", "Sweden",
"Nepal", "Cambodia", "Spain", "Belgium"), Total = c(34620, 89,
40, 32, 26, 24, 17, 16, 15, 14, 13, 12, 11, 10, 7, 7, 3, 3, 3,
3, 2, 1, 1, 1, 1, 1, 1, 1), Code = c("CHN", "JPN", "SGP", "THA",
"HKG", "KOR", "TWN", "MYS", "AUS", "DEU", "VNM", "USA", "FRA",
"MAC", "ARE", "CAN", "PHL", "IND", "ITA", "GBR", "RUS", "FIN",
"LKA", "SWE", "NPL", "KHM", "ESP", "BEL")), row.names = c(NA,
-28L), class = "data.frame")
case <- case[order(case$Country), ]
Country = map("world", fill = TRUE, plot = FALSE, regions = iso.expand(case$Code,regex = F))
IDs <- Country$names
Country <- map2SpatialPolygons(Country,
IDs=IDs,
proj4string=CRS("+proj=longlat +datum=WGS84"))
case[nrow(case) + 1, ] <- case[case$Code == "ESP",]
case$Country[nrow(case)] <- "Canary Islands"
case$Country[case$Country == "S. Korea"] <- "South Korea"
case$Country[case$Country == "U.K."] <- "UK"
case$Country[case$Country == "U.A.E."] <- "United Arab Emirates"
case$Total[case$Country == "China"] <- case$Total[case$Country == "China"] +
case$Total[case$Country == "Hong Kong"] +
case$Total[case$Country == "Macao"]
case <- case[-which(case$Country == "Hong Kong"), ]
case <- case[-which(case$Country == "Macao"), ]
case <- case[order(case$Country), ]
reps <- as.numeric(table(sapply(strsplit(IDs, ":"), function(x) x[1])))
case <- do.call(rbind, mapply(function(x, y){ x[rep(1,y),]},
split(case, case$Country),
reps,
SIMPLIFY = F))
pal <- colorNumeric(
palette = "Blues",
domain = as.numeric(case$Total))
case$labels <- sprintf(
"<strong>Country:%s</strong><br/>Total:%g",
case$Country, case$Total)%>% lapply(htmltools::HTML)
leaflet(Country) %>% addTiles() %>%
addPolygons(fillOpacity = 0.6, smoothFactor = 0.5, stroke = TRUE, weight = 1,
color = pal(as.numeric(case$Total)),
label = case$labels)
Obviously this is just a snapshot, but you can see China is coloured correctly.