Convert Character String to Matrix-CodePudding

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.)

CodePudding user response：

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))

CodePudding user response：

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

CodePudding user response：

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