如何在向量中的每个字符串中只保留唯一的单词 [英] How do keep only unique words within each string in a vector

问题描述

我的数据如下所示:

vector = c("hello I like to code hello","Coding is fun", "fun fun fun")

我想删除重复的单词(空格分隔)，即输出应该是这样的

I want to remove duplicate words (space delimited) i.e. the output should look like

vector_cleaned

vector_cleaned

[1] "hello I like to code"
[2] "coding is fun"
[3] "fun"

推荐答案

拆分它(strsplit 对空格)，使用 unique(在 lapply)，然后将其 paste 重新组合在一起:

Split it up (strsplit on spaces), use unique (in lapply), and paste it back together:

vapply(lapply(strsplit(vector, " "), unique), paste, character(1L), collapse = " ")
# [1] "hello i like to code" "coding is fun"        "fun"  

## OR
vapply(strsplit(vector, " "), function(x) paste(unique(x), collapse = " "), character(1L))

<小时>

根据评论更新

您始终可以编写一个自定义函数来与您的 vapply 函数一起使用.例如，这里有一个函数，它接受一个拆分字符串，删除短于特定字符数的字符串，并将唯一"设置作为用户选择.

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Update based on comments

You can always write a custom function to use with your vapply function. For instance, here's a function that takes a split string, drops strings that are shorter than a certain number of characters, and has the "unique" setting as a user choice.

myFun <- function(x, minLen = 3, onlyUnique = TRUE) {
  a <- if (isTRUE(onlyUnique)) unique(x) else x
  paste(a[nchar(a) > minLen], collapse = " ")
}

比较下面的输出，看看它是如何工作的.

Compare the output of the following to see how it would work.

vapply(strsplit(vector, " "), myFun, character(1L))
vapply(strsplit(vector, " "), myFun, character(1L), onlyUnique = FALSE)
vapply(strsplit(vector, " "), myFun, character(1L), minLen = 0)

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