Setting

My task looks similar to this one but not quite. Suppose I have a symmetric data frame looking like this

df <- data.frame(
    matrix(c(1, 7, 0, 5, 9, 0,
             7, 4, 0, 8, 2, 0, 
             0, 0, 0, 0, 0, 0, 
             5, 8, 0, 1, 1, 0, 
             9, 2, 0, 1, 1, 0, 
             0, 0, 0, 0, 0, 0), nrow=6, ncol=6)
)

It looks like this

  X1 X2 X3 X4 X5 X6
1  1  7  0  5  9  0
2  7  4  0  8  2  0
3  0  0  0  0  0  0
4  5  8  0  1  1  0
5  9  2  0  1  1  0
6  0  0  0  0  0  0

Because it's symmetric if a row is full of zeros, the corresponding column with the same index will also be full of zeros.

What I want to do

I want to drop all the rows and the columns that contain only zero (in general, I would like to drop all the rows and columns satisfying some condition). Ideally, I would like to use functions within the tidyverse. Would be great if I could use pipes somehow.

Is it possible to do this with pipes?

Important

I made a mistake, I think it's essential that the solution works for sparse matrices. Would it please be possible to have an implementation that works for dgCMatrix class? I.e. for sparse matrices?

When I try many of the tidyverse implementations below I get

Error in UseMethod("tbl_vars") : 
  no applicable method for 'tbl_vars' applied to an object of class "c('dgCMatrix', 'CsparseMatrix', 'dsparseMatrix', 'generalMatrix', 'dCsparseMatrix', 'dMatrix', 'sparseMatrix', 'compMatrix', 'Matrix', 'xMatrix', 'mMatrix', 'Mnumeric', 'replValueSp')"