r语言 - 从两列中检测相似的连续模式

Question

x1= c("Sunwood", "Greengrass", "bluesky")
x2= c("Sun wood", "green", "sky Pl")
testframe = data.frame(Address1=x1, Address2=x2) 

比较两列的第三列的输出应显示"是"。因为存在"太阳"、"绿色"和"天空"表示匹配。我们如何能够检测到它（最多三个连续字母）

Answer 1

这是一种tidyverse可能性：

testframe %>%
 mutate_if(is.factor, as.character) %>%
 mutate(Res = ifelse(str_detect(str_extract(Address1, "^.{3}"), 
                          fixed(str_extract(Address2, "^.{3}"), ignore_case = TRUE)), "Yes", "No"))
    Address1 Address2 Res
1    Sunwood Sun wood Yes
2 Greengrass    green Yes
3    bluesky   sky Pl  No

它检查"Address1"中的前三个元素是否与"Address2"中的前三个元素匹配（无论大小写如何）。如果是这样，则返回"是"，否则返回"否"。

或者手动将大小写设置为降低：

testframe %>%
 mutate_if(is.factor, as.character) %>%
 mutate(Res = ifelse(str_detect(tolower(str_extract(Address1, "^.{3}")), 
                                tolower(str_extract(Address2, "^.{3}"))), "Yes", "No"))

相同，但基于@PoGibas的想法进行了简化：

testframe %>%
 mutate_if(is.factor, as.character) %>%
 mutate(Res = ifelse(tolower(str_extract(Address1, "^.{3}")) == tolower(str_extract(Address2, "^.{3}")), "Yes", "No"))

或者只使用基本 R：

testframe$Address1 <- as.character(testframe$Address1)  
testframe$Address2 <- as.character(testframe$Address2)
testframe$Res <- ifelse(tolower(sub("^(.{3}).*", "\1", testframe$Address1)) %in% 
                         tolower(sub("^(.{3}).*", "\1", testframe$Address2)), "Yes", "No")
    Address1 Address2 Res
1    Sunwood Sun wood Yes
2 Greengrass    green Yes
3    bluesky   sky Pl  No

或者基本上和@PoGibas的想法一样：

testframe$Res <- ifelse(tolower(substring(testframe$Address1, 1, 3)) %in% 
                         tolower(substring(testframe$Address2, 1, 3)), "Yes", "No")