Könntest du mir für diese Rstudio code eine ausführliche Erklärung in ausgezeichnetem englisch schreiben:   
### Relation ###
zuordnung_vor_2023 <- prophet_100 %>%
  filter(Polzaehler == 1, as.Date(vbbeg) < as.Date('2023-01-01')) %>%
  select(aufrufID,lvid, LVIDEXT, pdid, c_tarifidZus, SAPSparte, vbbeg, vtabl, rbeg, risart) %>%
  left_join(join_GIC, by = c('LVIDEXT' = 'CONTRACT_ID_ORIGINAL')) %>%
  rename(GROUP_NAME = GROUP_NAME_old) %>%
  mutate(GROUP_NAME = as.character(GROUP_NAME))
  
c_tarifidZus_FLV_07 <- c('AXA0', 'AXA1', 'AXA2', 'AXA3', 'AXAH', 'BEZ_NICHT_RELEVANT','D05', 'D05R', 'D335', 'D35', 'D35R', 'D37R', 'D38R', 
                         'F30', 'F31', 'F32', 'F33','F35', 'F36', 'F37', 'F38', 'F40', 'F41', 'F42', 'F43', 'F45', 'F46', 'F47', 'F48',
                         'F50', 'F51', 'F52', 'F53', 'F55', 'F56', 'F57', 'F58','FL_X', 'FL_X0', 'FL_X1', 'FL_X2', 'FL_X3', 'FL_X4', 'FL_X6', 'FL_XA', 'FL_XH',
                         'FLF1', 'FLF3', 'FLXU', 'FLXP', 'I05','K05', 'K05', 'K05_H', 'K05U', 'K30','K35', 'K37', 'K40', 'K41','K42', 'K45', 'K46',
                         'M05', 'R25R', 'R25RA', 'R2R', 'R2RA', 'R2RH', 'R50R', 'R50RA', 'R75R', 'R75RA',
                         'S35', 'S37','T05', 'T20', 'T60', 'Z05','Z16','Z25','Z50','Z75')
  
c_tarifidZus_FLV_17 <- c('FLX0U', 'FLX1U', 'FLX2U', 'FLX3U', 'FLX4U', 'FLX6U','FLXAU', 'FLXHU',
                         'T05U', 'T20U', 'T60U', 'Z05U', 'Z16U', 'Z25U', 'Z50U', 'Z75U')
  
zuordnung_nach_2023 <- prophet_100 %>%
  filter(Polzaehler == 1, as.Date(vbbeg) >= as.Date('2023-01-01')) %>%
  select(aufrufID, lvid, LVIDEXT, pdid, c_tarifidZus, SAPSparte, vbbeg, vtabl, rbeg, risart) %>%
  mutate(
    VERSBEGGV_YEAR = as.numeric(format(vbbeg, '%Y')),
    GROUP_NAME_1 = case_when(
      risart == 'ABL' & SAPSparte == 'S01302' ~ '17',
      risart == 'ABL' & SAPSparte == 'S01353' ~ '03',
      risart == 'BU' ~ '17',
      risart == 'DD' ~ '17',
      risart == 'FLV' & c_tarifidZus %in% c_tarifidZus_FLV_07 ~ '07',
      risart == 'FLV' & c_tarifidZus %in% c_tarifidZus_FLV_17 ~ '17',
      risart == 'ILV' ~ '08',
      risart == 'REN' ~ '17',
      risart == 'ZUV' ~ '07',
    ),
    GROUP_NAME = ifelse(GROUP_NAME_1 == '17', '1017',
                        paste(formatC(VERSBEGGV_YEAR - 2000, width = 2, format = 'd', flag = '0'), GROUP_NAME_1, sep=''))
  ) %>%
  mutate(GROUP_NAME = ifelse(LVIDEXT %in% c('5500263661', '5500264425'), '1017', GROUP_NAME)) %>%
  select(-GROUP_NAME_1, -VERSBEGGV_YEAR)
  
zuordnung <- bind_rows(zuordnung_vor_2023, zuordnung_nach_2023)
                         
### CHECK ###
  
df1_selected <- zuordnung %>% select(LVIDEXT, GROUP_NAME) 
  
df2_selected <- prophet_100_out %>%
  select(LVIDEXT, GROUP_NAME_old) %>%
  rename(GROUP_NAME = GROUP_NAME_old)
  
num_mismatches <- zuordnung %>%
  select(LVIDEXT, GROUP_NAME) %>%
  left_join(df2_selected, by = 'LVIDEXT', suffix = c('_file1', '_file2')) %>%
  filter(GROUP_NAME_file1 != GROUP_NAME_file2 | 
           is.na(GROUP_NAME_file1) | 
           is.na(GROUP_NAME_file2)) %>%
  nrow()

print(num_mismatches)

comparison_df <- df1_selected %>%
  left_join(df2_selected, by = 'LVIDEXT', suffix = c('_file1', '_file2')) %>%
  mutate(Match = GROUP_NAME_file1 == GROUP_NAME_file2)