R - Avoiding for loops with automatic iteration -

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this contrived example i'm using understand r better. lets want subset character vector called "test". want return each element value third character last character. doesn't work:

test = c( "jane" , "jerry" , "joan" ) substr( test , 3 , length( test ) ) expecting: "ne" , "rry" , "an"

is there way without loop?

use nchar(). it's vectorized:

> test = c( "jane" , "jerry" , "joan" ) > substr( test , 3 , nchar( test ) ) [1] "ne"  "rry" "an"

given nchar return vector of lengths, , substr likewise vectorized, , expects work vector arguments, 1 potential puzzle why accepts scalar argument of 3. answer here scalars start , stop arguments recycled match length of input character vector. could, therefore, use 1:2 start argument , alternating complete , complete strings:

>      substr( test , 1:2 , nchar( test ) ) [1] "jane" "erry" "joan"

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