R：如何通过列名将列分配给矩阵

Question

我有一个形状正确的空矩阵（列和行）。 我想一次将列分配给这个矩阵。

allf <- matrix(0, nrow = 2*h, ncol = ncol(ally))
colnames(allf)<- colnames(train)

Here, allf has columns from AA, AB.... AZ. 

Now, I want to assign the values by column name. As in:

allf.AA <- someothermatrix['xyz']

Answer 1

这会做到的。

allf[,'AA'] <- someothermatrix[,'xyz']