Find part of string in another string

Question

How do I find a part of a string in another string. Below you can find some sample data:

a <- c("23,45,24,67,91,10")
b <- c("as.01,as.23,as55,as69")

The objective is to find any substring of a in b . Thus this should return TRUE since 23 is present in a and in b . I already tried functions such as

charmatch
grepl
match 

But all of these do not seem to fit my purpose. Any help is appreciated!

Answer 1

There may be an error in your inputs a and b:

a <- c("23","45","24","67","91","10")
b <- c("as.01","as.23","as55","as69")

> any(sapply(a, grepl, x=b))
[1] TRUE

Or only in your input a:

a <- c("23","45","24","67","91","10")
b <- c("as.01,as.23,as55,as69")

> any(sapply(a, grepl, x=b))
[1] TRUE

Or if no error:

> any(sapply(strsplit(a,',')[[1]], grepl, x=b))
[1] TRUE

Answer 2

You can avoid *apply loops and vectorize it using gsub in order to replace , to | and convert it to a valid regex expression.

grepl(gsub(",", "|", a, fixed = TRUE), b)
## [1] TRUE

This way, you also don't need to use any as it will return only one TRUE even if you have more than one matches, for example.

a <- "23,45,55,67,91,10"
b <- "as.01,as.23,as55,as69"

grepl(gsub(",", "|", a, fixed = TRUE), b)
## [1] TRUE