# colMax: Find row and column maximum values In xcms: LC-MS and GC-MS Data Analysis

## Description

Find row and column maximum values for numeric arrays.

## Usage

 ```1 2 3 4``` ```colMax(x, na.rm = FALSE, dims = 1) rowMax(x, na.rm = FALSE, dims = 1) which.colMax(x, na.rm = FALSE, dims = 1) which.rowMax(x, na.rm = FALSE, dims = 1) ```

## Arguments

 `x` an array of two or more dimensions, containing numeric values `na.rm` logical. Should missing values (including 'NaN') be omitted from the calculations? (not currently implemented) `dims` Which dimensions are regarded as "rows" or "columns" to maximize. For `rowMax`, the maximum is over dimensions ```dims+1, ...```; for `colMax` it is over dimensions `1:dims`.

## Details

These functions are designed to act like the `colSums` series of functions except that they only currently handle real arrays and will not remove `NA` values.

## Value

A numeric 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.

For the `which.*` functions, an integer array of suitable size, or a vector if the result is one-dimensional. The indecies returned are for accessing `x` one-dimensionally (i.e. `x[index]`). For `which.colMax()`, the actual row indecies my be determined using ```(which.colMax(x)-1) %% nrow(x) + 1```. For `which.rowMax()`, the actual column indecies may be determined using `ceiling(rowMax(x)/nrow(x))`.

## Author(s)

Colin A. Smith, csmith@scripps.edu

`colSums`