R在数据帧列上应用用户定义函数

Question

在R中，我有一个函数定义来计算两个字符串之间的交集：

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

我想在一个包含两个字符串列的数据框架上应用这个函数:data.selectedc(‘关键字’，'title')

keywords                                                                             title
1  Samsung UN48H6350 48" Samsung UN48H6350 48" Full 1080p Smart HDTV 120Hz with Wi-Fi +$50 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)

如何使用对这2列应用的apply函数来返回一个带有结果的新列？

Answer 1

首先，您的return语句确实会给您一个错误。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来解决问题。

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

只有当as.character是factor (而不是character)时，才有必要使用factor