Adding a character element to a numerical matrix

Question

I have a 2 x 30 matrix in R consisting of 1s and 2s. I was wondering how I could add an additional "p:" before each element of my matrix?

For example, p1: 1, p2: 2, p3: 1, p4: 2 and so on.

Here is what I tried with no success:

a <- matrix(rep(1:2, 30), 2, 30)
a <- paste0("p", 1:30, ":")

Answer 1

我们paste “P”与序列，然后paste ，与matrix “a”和分配输出回到“A”

a[] <- paste(paste0("p", 1:30), a, sep=": ")

Answer 2

使用 apply 的另一种方法：

apply(a, 2, function(x) paste('p', parent.frame()$i[], ': ', x, sep=''))