Count Values Using a Predicate

Counts values by rows/columns using a predicate function.

Usage

count(x, ...)

# S4 method for class 'data.frame'
count(x, f, margin = 1, negate = FALSE, na.rm = FALSE, ...)

# S4 method for class 'matrix'
count(x, f, margin = 1, negate = FALSE, na.rm = FALSE, ...)

Arguments

x

An R object (should be a matrix or a data.frame).

...

Further arguments to be passed to f.

f

A predicate function.

margin

A length-one numeric vector giving the subscripts which the function will be applied over (1 indicates rows, 2 indicates columns).

negate

A logical scalar: should the negation of f be used instead of f?

na.rm

A logical scalar: should NA values be stripped before the computation proceeds?

Value

A numeric vector.

See also

Other data preparation tools: append_column(), append_rownames(), assign(), compact(), detect(), discard(), get(), keep(), seek()

Author

N. Frerebeau

Examples

## Create a data matrix
X <- matrix(sample(1:10, 25, TRUE), nrow = 5, ncol = 5)

## Add NA
k <- sample(1:25, 3, FALSE)
X[k] <- NA
X
#>      [,1] [,2] [,3] [,4] [,5]
#> [1,]    2   NA    4    6   NA
#> [2,]    2    3    8    9    2
#> [3,]    8    1   10    9   10
#> [4,]    2    8   10    3   10
#> [5,]   NA    1   10    6    3

## Count missing values in rows
count(X, f = is.na, margin = 1)
#> [1] 2 0 0 0 1
## Count non-missing values in columns
count(X, f = is.na, margin = 2, negate = TRUE)
#> [1] 4 4 5 5 4