Split string into substrings of given length with remainder

Question

Given a string such as:

text <- "abcdefghijklmnopqrstuvwxyz"

I would like to chop the string into substrings, for example length 10, and keep the remainder:

"abcdefghij"
"klmnopqrst"
"uvwxyz"

All the methods I know for creating substrings will not give me the remainder substring with 6 characters. I have tried answers from previous similar questions such as:

> substring(text, seq(1, nchar(text), 10), seq(10, nchar(text), 10))
[1] "abcdefghij" "klmnopqrst" ""  

Any advice as to how to obtain all the substrings of the desired length and any remainder strings would be much appreciated.

Answer 1

Try

strsplit(text, '(?<=.{10})', perl=TRUE)[[1]]
#[1] "abcdefghij" "klmnopqrst" "uvwxyz" 

Or you can use the library(stringi) for faster approach

library(stringi)
stri_extract_all_regex(text, '.{1,10}')[[1]]
#[1] "abcdefghij" "klmnopqrst" "uvwxyz"    

Answer 2

The vectors that you use for the first and last arguments in substring can exceed the number of characters in the string without error/warning/problems. So you can do

text <- "abcdefghijklmnopqrstuvwxyz"

sq <- seq.int(to = nchar(text), by = 10)
substring(text, sq, sq + 9)
# [1] "abcdefghij" "klmnopqrst" "uvwxyz"   

Answer 3

Here is a way using strapplyc involving a fairly simple regular expression. It works because .{1,10} always matches the longest string that is no longer than 10 characters:

library(gsubfn)
strapplyc(text, ".{1,10}", simplify = c)

giving:

[1] "abcdefghij" "klmnopqrst" "uvwxyz"

Visualization This regular expression is simple enough that it does not really require a visualization but here is one anyways:

.{1,10}

Debuggex Demo