换字规则

Question

我有一个这样的数据框：

df <- data.frame(id = c(1,2), keywords = c("google, yahoo, air, cookie", "cookie, air"))

我想实施如下规则：

stocks <- c("google, yahoo")
climate <- c("air")
cuisine <- c("cookie")

并获得如下结果：

df_ne <- data.frame(id = c(1,2), keywords = c("stocks, climate, cuisine", "climate, cuisine")

怎么做呢？

Answer 1

您可以使用str_replace_all包中的stringr

library(dplyr)
library(stringr)
df <- data.frame(id = c(1,2), keywords = c("google, yahoo, air, cookie", "cookie, air"))

df %>% 
  mutate(keywords = str_replace_all(keywords, 
    c("google, yahoo" = "stocks","air" = "climate", "cookie" = "cuisine")))

Answer 2

我喜欢霍兰德答案（+1），但是您也可以使用tidytext::unnest_tokens()，如果您要输入的单词数不止六个，这会更简单。

首先，您可以创建一个映射df：

mapped <- rbind (data.frame(word_a = stocks, type = "stock", stringsAsFactors = F),
                 data.frame(word_a = climate, type = "climate", stringsAsFactors = F),
                 data.frame(word_a = cuisine, type = "cuisine", stringsAsFactors = F))

现在，您可以使用上述功能将几个未嵌套的df达到目标：

library(tidytext)
library(stringr)
library(tidyverse)
mapped <- mapped %>%  unnest_tokens(word, word_a)

df %>% 
unnest_tokens(word, keywords) %>%    # split words
left_join(mapped) %>%                # join to map
group_by(id) %>%                     # group
summarise(keywords = str_c(unique(type), collapse = ",")) # collapse the word (unique)

# A tibble: 2 x 2
     id keywords             
  <dbl> <chr>                
1     1 stock,climate,cuisine
2     2 cuisine,climate   

请注意，由于第二行的顺序与第一行df中的对应单词顺序相同，所以第二行的单词而不是预期的输出。

---

有数据：

df <- data.frame(id = c(1,2), keywords = c("google, yahoo, air, cookie", "cookie, air"), stringsAsFactors = F)


stocks <- c("google, yahoo")
climate <- c("air")
cuisine <- c("cookie")

Answer 3

从这里开始，这是一个幼稚的解决方案：

key <- list(
  stocks = c("google", "yahoo"),
  climate = "air",
  cuisine = "cookie"
)

df2 <- df
#replace by the key
for (k in 1:length(key)){
  for(sk in key[[k]]){
    df2$keywords <- gsub(sk, names(key)[k], df2$keywords, fixed = TRUE)
  }
}
#remove duplicated items
df2$keywords <- lapply(strsplit(df2$keywords, ", "), function(l) paste(unique(l), sep = ","))