Count number of zeros in columns and rows of large matrices

Produces the same result as applying sum(x == 0) to each row or column.

Usage

colZeros(x)

rowZeros(x)

Arguments

x

matrix or Matrix object

Examples

mt <- Matrix::rsparsematrix(100, 100, 0.01)
colZeros(mt)
#>   [1]  97  99  99 100  98  99  99  95  98  99  99  99  99  99  98  99  99  98
#>  [19]  99  99  99 100  99  99 100  99 100 100  98 100  98  99  99  99  99 100
#>  [37] 100  99  97 100 100  99  99 100  98 100 100  99 100  98  99  99 100 100
#>  [55]  99  99 100  98  99 100 100  97  99 100  99 100  96 100  99 100 100 100
#>  [73] 100 100  97  99  97 100 100 100  99  99  98 100 100  98  99  98  97  98
#>  [91] 100 100  98  98  98  99  98  99 100 100
apply(mt, 2, function(x) sum(x == 0)) # the same
#>   [1]  97  99  99 100  98  99  99  95  98  99  99  99  99  99  98  99  99  98
#>  [19]  99  99  99 100  99  99 100  99 100 100  98 100  98  99  99  99  99 100
#>  [37] 100  99  97 100 100  99  99 100  98 100 100  99 100  98  99  99 100 100
#>  [55]  99  99 100  98  99 100 100  97  99 100  99 100  96 100  99 100 100 100
#>  [73] 100 100  97  99  97 100 100 100  99  99  98 100 100  98  99  98  97  98
#>  [91] 100 100  98  98  98  99  98  99 100 100