从R中的另一个数据帧查找所有字符串匹配 [英] Finding all string matches from another dataframe in R

问题描述

我在R中相对较新。

我有一个数据框 locs ，其中有1个变量 V1 ，看起来像：

I have a dataframe locs that has 1 variable V1 and looks like:

V1
edmonton general hospital
cardiovascular institute, hospital san carlos, madrid spain
hospital of santa maria, lisbon, portugal

和另一个具有以下两个变量的数据框 cities ：

and another dataframe cities that has two variables that look like this:

city              country
edmonton          canada
san carlos        spain
los angeles       united states
santa maria       united states
tokyo             japan
madrid            spain
santa maria       portugal
lisbon            portugal

我想在中创建两个新变量locs 与 city 内的任何 V1 字符串匹配相关，从而使位置看起来像这样：

I want to create two new variables in locs that relates any string match of V1 within city so that locs looks like this:

V1                                            city                  country                      
edmonton general hospital                     edmonton              canada
hospital san carlos, madrid spain             san carlos, madrid    spain
hospital of santa maria, lisbon, portugal     santa maria, lisbon   portugal, united states

注意事项： V1 可能有多个国家/地区名称。另外，如果有一个重复的国家（例如，圣卡洛斯和马德里都在西班牙），那么我只想要该国家的一个实例。

A few things to note: V1 may have multiple country names. Also, if there is a repeat country (for instance, both san carlos and madrid are in spain), then I only want one instance of the country.

请告知。

谢谢。

推荐答案

使用 tidyverse 和 stringr 。 locs2 是最终输出。

A solution using tidyverse and stringr. locs2 is the final output.

library(tidyverse)
library(stringr)

locs2 <- locs %>%
  rowwise() %>%
  mutate(city = list(str_match(V1, cities$city))) %>%
  unnest() %>%
  drop_na(city) %>%
  left_join(cities, by = "city") %>%
  group_by(V1) %>%
  summarise_all(funs(toString(sort(unique(.)))))

结果

locs2 %>% as.data.frame()
                                                           V1                city                 country
1 cardiovascular institute, hospital san carlos, madrid spain  madrid, san carlos                   spain
2                                   edmonton general hospital            edmonton                  canada
3                   hospital of santa maria, lisbon, portugal lisbon, santa maria portugal, united states

DATA

library(tidyverse)

locs <- data_frame(V1 = c("edmonton general hospital",
                   "cardiovascular institute, hospital san carlos, madrid spain",
                   "hospital of santa maria, lisbon, portugal"))

cities <- read.table(text = "city              country
edmonton          canada
'san carlos'        spain
'los angeles'       'united states'
'santa maria'       'united states'
tokyo             japan
madrid            spain
'santa maria'       portugal
lisbon            portugal",
                     header = TRUE, stringsAsFactors = FALSE)

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