您当然可以获得存储在countrycodes中的“国家”向量，这些国家是您自己的数据中缺少的：

library(countrycode)

codelist$country.name.en[sapply(codelist$country.name.en.regex, function(x) {
  !any(grepl(x, df$country, perl = TRUE, ignore = TRUE))
  })]
#>   [1] "Afghanistan"                               
#>   [2] "Åland Islands"                             
#>   [3] "American Samoa"                            
#>   [4] "Andorra"                                   
#>   [5] "Anguilla"                                  
#>   [6] "Antarctica"                                
#>   [7] "Aruba"                                     
#>   [8] "Austria-Hungary"                           
#>   [9] "Baden"                                     
#>  [10] "Bavaria"                                   
#>  [11] "Belize"                                    
#>  [12] "Benin"                                     
#>  [13] "Bermuda"                                   
#>  [14] "Bouvet Island"                             
#>  [15] "British Indian Ocean Territory"            
#>  [16] "British Virgin Islands"                    
#>  [17] "Brunswick"                                 
#>  [18] "Burundi"                                   
#>  [19] "Cameroon"                                  
#>  [20] "Cape Verde"                                
#>  [21] "Caribbean Netherlands"                     
#>  [22] "Cayman Islands"                            
#>  [23] "Central African Republic"                  
#>  [24] "Chad"                                      
#>  [25] "Channel Islands"                           
#>  [26] "Christmas Island"                          
#>  [27] "Cocos (Keeling) Islands"                   
#>  [28] "Comoros"                                   
#>  [29] "Congo - Brazzaville"                       
#>  [30] "Cook Islands"                              
#>  [31] "Curaçao"                                   
#>  [32] "Cyprus"                                    
#>  [33] "Czechoslovakia"                            
#>  [34] "Equatorial Guinea"                         
#>  [35] "Eswatini"                                  
#>  [36] "Falkland Islands"                          
#>  [37] "Faroe Islands"                             
#>  [38] "French Guiana"                             
#>  [39] "French Polynesia"                          
#>  [40] "French Southern Territories"               
#>  [41] "Gambia"                                    
#>  [42] "German Democratic Republic"                
#>  [43] "Gibraltar"                                 
#>  [44] "Greenland"                                 
#>  [45] "Grenada"                                   
#>  [46] "Guadeloupe"                                
#>  [47] "Guam"                                      
#>  [48] "Guernsey"                                  
#>  [49] "Guinea-Bissau"                             
#>  [50] "Haiti"                                     
#>  [51] "Hamburg"                                   
#>  [52] "Hanover"                                   
#>  [53] "Heard & McDonald Islands"                  
#>  [54] "Hesse Electoral"                           
#>  [55] "Hesse Grand Ducal"                         
#>  [56] "Hesse-Darmstadt"                           
#>  [57] "Hesse-Kassel"                              
#>  [58] "Hong Kong SAR China"                       
#>  [59] "Isle of Man"                               
#>  [60] "Jersey"                                    
#>  [61] "Kiribati"                                  
#>  [62] "Kosovo"                                    
#>  [63] "Liberia"                                   
#>  [64] "Libya"                                     
#>  [65] "Macao SAR China"                           
#>  [66] "Maldives"                                  
#>  [67] "Mali"                                      
#>  [68] "Marshall Islands"                          
#>  [69] "Martinique"                                
#>  [70] "Mayotte"                                   
#>  [71] "Mecklenburg Schwerin"                      
#>  [72] "Micronesia (Federated States of)"          
#>  [73] "Modena"                                    
#>  [74] "Montenegro"                                
#>  [75] "Montserrat"                                
#>  [76] "Mozambique"                                
#>  [77] "Nassau"                                    
#>  [78] "Nauru"                                     
#>  [79] "Netherlands Antilles"                      
#>  [80] "New Caledonia"                             
#>  [81] "Niue"                                      
#>  [82] "Norfolk Island"                            
#>  [83] "North Korea"                               
#>  [84] "Northern Mariana Islands"                  
#>  [85] "Oldenburg"                                 
#>  [86] "Orange Free State"                         
#>  [87] "Palestinian Territories"                   
#>  [88] "Parma"                                     
#>  [89] "Piedmont-Sardinia"                         
#>  [90] "Pitcairn Islands"                          
#>  [91] "Prussia"                                   
#>  [92] "Puerto Rico"                               
#>  [93] "Republic of Vietnam"                       
#>  [94] "Réunion"                                   
#>  [95] "Saint Martin (French part)"                
#>  [96] "São Tomé & Príncipe"                       
#>  [97] "Sardinia"                                  
#>  [98] "Saxe-Weimar-Eisenach"                      
#>  [99] "Saxony"                                    
#> [100] "Serbia and Montenegro"                     
#> [101] "Seychelles"                                
#> [102] "Sierra Leone"                              
#> [103] "Sint Maarten"                              
#> [104] "Solomon Islands"                           
#> [105] "Somalia"                                   
#> [106] "Somaliland"                                
#> [107] "South Georgia & South Sandwich Islands"    
#> [108] "South Sudan"                               
#> [109] "St. Barthélemy"                            
#> [110] "St. Helena"                                
#> [111] "St. Kitts & Nevis"                         
#> [112] "St. Lucia"                                 
#> [113] "St. Pierre & Miquelon"                     
#> [114] "St. Vincent & Grenadines"                  
#> [115] "Svalbard & Jan Mayen"                      
#> [116] "Timor-Leste"                               
#> [117] "Togo"                                      
#> [118] "Tokelau"                                   
#> [119] "Turkmenistan"                              
#> [120] "Turks & Caicos Islands"                    
#> [121] "Tuscany"                                   
#> [122] "Tuvalu"                                    
#> [123] "Two Sicilies"                              
#> [124] "U.S. Virgin Islands"                       
#> [125] "United Arab Republic"                      
#> [126] "United Province CA"                        
#> [127] "United States Minor Outlying Islands (the)"
#> [128] "Vanuatu"                                   
#> [129] "Vatican City"                              
#> [130] "Wallis & Futuna"                           
#> [131] "Western Sahara"                            
#> [132] "Wuerttemburg"                              
#> [133] "Würtemberg"                                
#> [134] "Yemen Arab Republic"                       
#> [135] "Yemen People's Republic"                   
#> [136] "Yugoslavia"                                
#> [137] "Zanzibar"

然而，虽然这包含了许多从您的数据中缺失的现存国家（如阿富汗，伯利兹，贝宁等），但其中一些是半自治地区，它们本身不是国家（泽西岛，桑给巴尔，直布罗陀）或历史上不再存在的国家（例如。南斯拉夫）。
为了过滤掉不是当前国家的条目，我可能会使用类似rnaturalearth的东西：

missing <- codelist$country.name.en[sapply(codelist$country.name.en.regex, 
                                function(x) {
  !any(grepl(x, df$country, perl = TRUE, ignore = TRUE))
  })]

missing[missing %in% 
          rnaturalearth::ne_countries(scale = 110, returnclass = "sf")$name]
#>  [1] "Afghanistan"   "Antarctica"    "Belize"        "Benin"        
#>  [5] "Burundi"       "Cameroon"      "Chad"          "Cyprus"       
#>  [9] "Gambia"        "Greenland"     "Guinea-Bissau" "Haiti"        
#> [13] "Kosovo"        "Liberia"       "Libya"         "Mali"         
#> [17] "Montenegro"    "Mozambique"    "New Caledonia" "North Korea"  
#> [21] "Puerto Rico"   "Sierra Leone"  "Somalia"       "Somaliland"   
#> [25] "Timor-Leste"   "Togo"          "Turkmenistan"  "Vanuatu"

这为您提供了一个合理的28个当前国家的列表，这些国家不在您的原始列表中。其中，大多数是联合国成员国，但并非所有都是（据我所知，格陵兰岛，南极洲，科索沃，新喀里多尼亚，索马里兰和波多黎各do not have independent representation在撰写本文时在联合国）
创建于2023-09-28使用reprex v2.0.2