colSums {base} | R Documentation |

## Form Row and Column Sums and Means

### Description

Form row and column sums and means for numeric arrays.

### Usage

colSums (x, na.rm = FALSE, dims = 1)
rowSums (x, na.rm = FALSE, dims = 1)
colMeans(x, na.rm = FALSE, dims = 1)
rowMeans(x, na.rm = FALSE, dims = 1)

### Arguments

`x` |
an array of two or more dimensions, containing numeric,
complex, integer or logical values, or a numeric data frame. |

`na.rm` |
logical. Should missing values (including `NaN` )
be omitted from the calculations? |

`dims` |
Which dimensions are regarded as “rows” or
“columns” to sum over. For `row*` , the sum or mean is
over dimensions `dims+1, ...` ; for `col*` it is over
dimensions `1:dims` . |

### Details

These functions are equivalent to use of `apply`

with
`FUN = mean`

or `FUN = sum`

with appropriate margins, but
are a lot faster. As they are written for speed, they blur over some
of the subtleties of `NaN`

and `NA`

. If ```
na.rm =
FALSE
```

and either `NaN`

or `NA`

appears in a sum, the
result will be one of `NaN`

or `NA`

, but which might be
platform-dependent.

### Value

A numeric or complex array of suitable size, or a vector if the result is
one-dimensional. The `dimnames`

(or `names`

for a vector
result) are taken from the original array.

If there are no values in a range to be summed over (after removing
missing values with `na.rm = TRUE`

), that
component of the output is set to `0`

(`*Sums`

) or `NA`

(`*Means`

), consistent with `sum`

and
`mean`

.

### See Also

`apply`

, `rowsum`

### Examples

## Compute row and column sums for a matrix:
x <- cbind(x1 = 3, x2 = c(4:1, 2:5))
rowSums(x); colSums(x)
dimnames(x)[[1]] <- letters[1:8]
rowSums(x); colSums(x); rowMeans(x); colMeans(x)
x[] <- as.integer(x)
rowSums(x); colSums(x)
x[] <- x < 3
rowSums(x); colSums(x)
x <- cbind(x1 = 3, x2 = c(4:1, 2:5))
x[3, ] <- NA; x[4, 2] <- NA
rowSums(x); colSums(x); rowMeans(x); colMeans(x)
rowSums(x, na.rm = TRUE); colSums(x, na.rm = TRUE)
rowMeans(x, na.rm = TRUE); colMeans(x, na.rm = TRUE)
## an array
dim(UCBAdmissions)
rowSums(UCBAdmissions); rowSums(UCBAdmissions, dims = 2)
colSums(UCBAdmissions); colSums(UCBAdmissions, dims = 2)
## complex case
x <- cbind(x1 = 3 + 2i, x2 = c(4:1, 2:5) - 5i)
x[3, ] <- NA; x[4, 2] <- NA
rowSums(x); colSums(x); rowMeans(x); colMeans(x)
rowSums(x, na.rm = TRUE); colSums(x, na.rm = TRUE)
rowMeans(x, na.rm = TRUE); colMeans(x, na.rm = TRUE)

[Package

*base* version 2.1.0

Index]