查找以逗号分隔的字符串出现次数,并输出字符串

时间:2017-04-07 02:01:55

标签: r string dataframe

我正在做一个实体消歧项目,我有一个同名作者的数据框,其中包含以下列:author IDcoauthor names

我需要找到作者ID所识别的作者与他/她曾经合作过的所有合着者之间的合作数量。

以下是数据框的示例:

author.ID             coauthor.names
   1                  J Smith, A Greer
   1                  J Adams, J Smith
   2                  D Richardson, J Smith

我希望输出为:

author.ID     coauthor.name     collaboration.times
   1             J Smith                2
   1             J Adams                1
   1             A Greer                1
   2             D Richardson           1
   2             J Smith                1

我尝试将作者的所有共同作者(用逗号分隔)和特定的作者ID组合成一个大字符串,我将在这个巨大的字符串中使用来自str_count包的stringr,但我不知道我是否正在解决这个问题。

是否有更有效或更优雅的方法来解决此问题?

感谢。

1 个答案:

答案 0 :(得分:3)

假设你正在处理这样的数据:

mydf <- structure(list(author.ID = c(1L, 1L, 2L), coauthor.names = c("J Smith, A Greer", 
    "J Adams, J Smith", "D Richardson, J Smith")), .Names = c("author.ID", 
    "coauthor.names"), row.names = c(NA, 3L), class = "data.frame")
mydf
##   author.ID        coauthor.names
## 1         1      J Smith, A Greer
## 2         1      J Adams, J Smith
## 3         2 D Richardson, J Smith

...您可以从我的“splitstackshape”软件包中尝试cSplit,然后从“data.table”聚合.N

library(splitstackshape)
cSplit(mydf, "coauthor.names", ",", "long")[
  , list(collaboaration.times = .N), .(author.ID, coauthor.names)][]
#    author.ID coauthor.names collaboaration.times
# 1:         1        J Smith                    2
# 2:         1        A Greer                    1
# 3:         1        J Adams                    1
# 4:         2   D Richardson                    1
# 5:         2        J Smith                    1

假设你正在处理这样的数据:

mydf2 <- structure(list(author.ID = c(1L, 1L, 2L), coauthor.names = structure(list(
        c("J Smith", "A Greer"), c("J Adams", "J Smith"), c("D Richardson", 
        "J Smith")), class = "AsIs")), .Names = c("author.ID", "coauthor.names"
    ), row.names = c(NA, 3L), class = "data.frame")
mydf2
##   author.ID coauthor.names
## 1         1   J Smith,....
## 2         1   J Adams,....
## 3         2   D Richar....

...你可以从listCol_l开始(再次从“splitstackshape”开始)然后以相同的方式计数。

listCol_l(mydf2, "coauthor.names")[
  , list(collaboration.times = .N), .(author.ID, coauthor.names_ul)]
#    author.ID coauthor.names_ul collaboration.times
# 1:         1           J Smith                   2
# 2:         1           A Greer                   1
# 3:         1           J Adams                   1
# 4:         2      D Richardson                   1
# 5:         2           J Smith                   1

“tidyverse”等价物可能是这样的:

library(tidyverse)
# For a single character string as "coauthor.names"
mydf %>% 
  mutate(coauthor.names = lapply(strsplit(coauthor.names, ","), trimws)) %>%
  unnest() %>% 
  group_by(author.ID, coauthor.names) %>% 
  summarise(collaboration.times = n())

# If "coauthor.names" is already a `list`.
mydf2 %>%
  unnest() %>%
  group_by(author.ID, coauthor.names) %>%
  summarise(collaboration.times = n())