Question

我有一个包含两列的数据框：

df = data.frame(animals = c("cat; dog; bird", "dog; bird", "bird"), sentences = c("the cat is brown; the dog is barking; the bird is green and blue","the dog is black; the bird is yellow and blue", "the bird is blue"), stringsAsFactors = F)

我需要整个“句子”列中每一行上所有“动物”的出现总数。

例如：“动物”第一行c（“ cat; dog; bird”）= sum_occurrences_sentences_column（cat = 1）+（dog = 2）+（bird = 3）= 6。

结果将是第三列，如下所示：

df <- cbind( sum_accurrences_sentences_column = c("6", "5", "3"), df)

我尝试了以下代码，但它们不起作用。

df[str_split(df$animals, ";") %in% df$sentences, ]

str_count(df$sentences, str_split(df$animals, ";"))

任何帮助将不胜感激:)

Answer 1

这是一个基本的R解决方案：

首先用;删除所有gsub，然后将句子列和unlist分成一个向量：

split_sentence_column = unlist(strsplit(gsub(';','',df$sentences),' '))

然后建立一个for循环，并为每行获取动物的向量，用%in%检查动物列表中的哪些句子列动物，然后对所有TRUE个案求和。然后，我们可以将其直接分配给新的df列：

for(i in 1:nrow(df)){
  animals = unlist(strsplit(df$animals[i], '; '))
  df$sum_occurrences_sentences_column[i] = sum(split_sentence_column %in% animals)
}

> df
         animals                                                        sentences sum_occurrences_sentences_column
1 cat; dog; bird the cat is brown; the dog is barking; the bird is green and blue                                6
2      dog; bird                    the dog is black; the bird is yellow and blue                                5
3           bird                                                 the bird is blue                                3

Answer 2

一种map()方式来操纵第一列中的每只动物。

library(tidyverse)
string <- unlist(str_split(df$sentences, ";"))

df %>% rowwise %>%
  mutate(SUM = str_split(animals, "; ", simplify = T) %>%
    map( ~ str_count(string, .)) %>%
    unlist %>% sum)

#   animals        sentences                                           SUM
#   <chr>          <chr>                                               <int>
# 1 cat; dog; bird the cat is brown; the dog is barking; the bird...   6
# 2 dog; bird      the dog is black; the bird is yellow and blue       5
# 3 bird           the bird is blue                                    3

在R中的列中搜索多个值

2 个答案: