Convert Character String to Matrix

user_16900910 0
Viewed 80

I have a large (rectangular) vector of strings, e.g:

my.strings <- c("1234567", "1234567", "1234567", "1234567")

which I would like to convert to a matrix:

#      [,1] [,2] [,3] [,4] [,5] [,6] [,7]
# [1,]    1    2    3    4    5    6    7
# [2,]    1    2    3    4    5    6    7
# [3,]    1    2    3    4    5    6    7
# [4,]    1    2    3    4    5    6    7

Is there a simple way to do this in R? (Unfortunately, yes the strings of numbers are indeed character strings and not numeric.)

r matrix string
3 Answers

We could use strsplit to split at '', and then rbind the list elements after converting the type

do.call(rbind, type.convert(strsplit(my.strings, ""), as.is = TRUE))
      [,1] [,2] [,3] [,4] [,5] [,6] [,7]
[1,]    1    2    3    4    5    6    7
[2,]    1    2    3    4    5    6    7
[3,]    1    2    3    4    5    6    7
[4,]    1    2    3    4    5    6    7

Here, we assume the strings have the same number of characters (nchar). If it is different, the lengths will be different and thus have to pad NA before reshaping to matrix

lst1 <- type.convert(strsplit(my.strings, ""), as.is = TRUE)
mx <- max(lengths(lst1))
do.call(rbind, lapply(lst1, `length<-`, mx))
user_37322710

Another possible solution:

library(tidyverse)

my.strings <- c("1234567", "1234567", "1234567", "1234567")

my.strings %>% 
  sapply(function(x) str_split(x,"") %>% unlist %>% as.numeric) %>% 
  unname %>% t

#>      [,1] [,2] [,3] [,4] [,5] [,6] [,7]
#> [1,]    1    2    3    4    5    6    7
#> [2,]    1    2    3    4    5    6    7
#> [3,]    1    2    3    4    5    6    7
#> [4,]    1    2    3    4    5    6    7
user_115644870

Here's another way:

matrix(as.numeric(unlist(strsplit(my.strings, ""))), nrow = length(my.strings), byrow=T)

     [,1] [,2] [,3] [,4] [,5] [,6] [,7]
[1,]    1    2    3    4    5    6    7
[2,]    1    2    3    4    5    6    7
[3,]    1    2    3    4    5    6    7
[4,]    1    2    3    4    5    6    7
user_134606020
Related