我如何 output 一个矩阵向量或 dataframe ，其中每个元素都是从每一行连接的字符串？

Question

I have a matrix (or dataframe):

m1 <- matrix(letters[1:8], ncol = 2, byrow=TRUE)

     [,1] [,2]
[1,] "a"  "b" 
[2,] "c"  "d" 
[3,] "e"  "f" 
[4,] "g"  "h" 

Desired output:

vec1 = c("ab", "cd", "ef", "gh")

I would prefer this would work for a matrix of any column or row size. Base R and dplyr appreciated.

Answer 1

We can either convert to data.frame and then paste with do.call

do.call(paste, c(as.data.frame(m1), sep=''))
#[1] "ab" "cd" "ef" "gh"

Or a less efficient option is apply

apply(m1, 1, paste, collapse = '')

---

With tidyverse , we can use reduce with str_c

library(dplyr)
library(purrr)
library(stringr)
as_tibble(m1) %>% 
    reduce(str_c, sep="")
 #[1] "ab" "cd" "ef" "gh"

Or if there are only two column, extract the columns by index and use paste0

paste0(m1[,1], m1[,2])

---

Or with asplit , split the matrix by column into a list of vector s and then use do.call

do.call(paste, c(asplit(m1, 2), sep=''))