R 在数据框列上应用用户定义函数

Question

在 R 中，我定义了一个函数来计算 2 个字符串之间的交集：

containedin <- function(t1,t2){
  return length(Reduce(intersect, strsplit(c(t1,t2), "\s+"))) 
}

我想将此函数应用于包含 2 个字符串列的数据框： data.selected[c('keywords','title')]

keywords                                                                             title
1  Samsung UN48H6350 48" Samsung UN48H6350 48" Full 1080p Smart HDTV 120Hz with Wi-Fi + Visa Gift Card
2  Samsung UN48H6350 48"     Samsung UN48H6350 48" Full HD Smart LED TV -Bundle- (See Below for Contents)
3  Samsung UN48H6350 48"      Samsung UN48H6350 48" Class Full HD Smart LED TV -BUNDLE- See below Details
4  Samsung UN48H6350 48"     Samsung UN48H6350 48" Full HD Smart LED TV With BD-H5100 Blu-ray Disc Player
5  Samsung UN48H6350 48"                 Samsung UN48H6350 48" Smart 1080p Clear Motion Rate 240 LED HDTV
6  Samsung UN48H6350 48"            Samsung UN48H6350 - 48-Inch Full HD 1080p Smart HDTV 120Hz with Wi-Fi
7  Samsung UN48H6350 48"               Samsung 6350 Series UN48H6350 48" 1080p HD LED LCD Internet TV NEW
8  Samsung UN48H6350 48"  Samsung Un48h6350af 75" 1080p Led-lcd Tv - 16:9 - Hdtv 1080p - (un75h6350afxza)
9  Samsung UN48H6350 48"                         Samsung UN48H6350 - 48" HD 1080p Smart HDTV 120Hz Bundle
10 Samsung UN48H6350 48"   Samsung UN48H6350 - 48-Inch Full HD 1080p Smart HDTV 120Hz with Wi-Fi, (R#416)

我如何使用 apply 函数应用到这两列，return 一个新的结果列？

Answer 1

首先，您的 return 语句确实应该给您一个错误。你可能是说

containedin <- function(t1,t2){
  length(Reduce(intersect, strsplit(c(t1,t2), "\s+"))) 
}

无论如何，您可以使用mapply来解决您的问题。

mapply(containedin, 
       as.character(data.selected[, 'keywords']), 
       as.character(data.selected[, 'title']))

仅当 class(data.selected[, 'keywords']) 为 factor（而不是 character）时才需要 as.character

R 在数据框列上应用用户定义函数

R apply user define function on data frame columns

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