Заполнение столбца в dataframe основанный на колонке в другом dataframe в г

Question

У меня есть dataframe комментариев, которая выглядит так (df1)

Comments 
Apple laptops are really good for work,we should buy them 
Apple Iphones are too costly,we can resort to some other brands 
Google search is the best search engine 
Android phones are great these days 
I lost my visa card today 

У меня есть еще один dataframe имен merchent, который выглядит следующим образом (df2):

Merchant_Name 
Google 
Android 
Geoni 
Visa 
Apple 
MC 
WallMart 

Если MERCHANT_NAME в df2 появляется в комментарий в ДФ 1, добавьте это имя торговца к второй колонке в df1 в матче R.The не должно быть точным приближением match.An является то, что required.Also, df1 содержит около 500K строк! Мой последний ooutput ДФ может выглядеть следующим образом

Comments              Merchant 
Apple laptops are really good for work,we should buy them  Apple 
Apple Iphones are too costly,we can resort to some other brands Apple 
Google search is the best search engine       Google 
Android phones are great these days        Android 
I lost my visa card today          Visa 

Как я могу сделать это и эффективно в R. ?? Thanks

Answer 1

Это работа для regex. Проверьте команду grepl внутри lapply.

comments = c(
    'Apple laptops are really good for work,we should buy them', 
    'Apple Iphones are too costly,we can resort to some other brands', 
    'Google search is the best search engine ', 
    'Android phones are great these days', 
    'I lost my visa card today' 
) 

brands = c(
    'Google', 
    'Android', 
    'Geoni', 
    'Visa', 
    'Apple', 
    'MC', 
    'WallMart' 
) 

brandinpattern = lapply(
    brands, 
    function(brand) { 
     commentswithbrand = grepl(x = tolower(comments), pattern = tolower(brand)) 
     if (sum(commentswithbrand) > 0) { 
     data.frame(
      comment = comments[commentswithbrand], 
      brand = brand 
     ) 
     } else { 
     data.frame() 
     } 
    } 
) 

brandinpattern = do.call(rbind, brandinpattern) 


> do.call(rbind, brandinpattern) 
                  comment brand 
1      Google search is the best search engine Google 
2        Android phones are great these days Android 
3          I lost my visa card today Visa 
4  Apple laptops are really good for work,we should buy them Apple 
5 Apple Iphones are too costly,we can resort to some other brands Apple 

Answer 2

Попробуйте

final_df <- data.frame(Comments = character(), Merchant_Name = character(), stringsAsFactors = F) 

for(i in df1$Comments){ 
    for(j in df2$Merchant_Name){ 
     if(grepl(tolower(j),tolower(i))){ 
      final_df[nrow(final_df) + 1,] <- c(i, j) 
      break 
     } 
    } 
} 


final_df 

##              comments brands 
##1  Apple laptops are really good for work,we should buy them Apple 
##2 Apple Iphones are too costly,we can resort to some other brands Apple 
##3      Google search is the best search engine Google 
##4        Android phones are great these days Android 
##5          I lost my visa card today Visa