R: Compute the Number of Non-missing Observations

nobs {gdata} | R Documentation

## Compute the Number of Non-missing Observations

### Description

Compute the number of non-missing observations. Provides a 'default' method to handle vectors, and a method for data frames.

### Usage

    nobs(object, ...)
    ## Default S3 method:
    nobs(object, ...)
    ## S3 method for class 'data.frame'
    nobs(object, ...)
    ## S3 method for class 'lm'
    nobs(object, ...)

### Arguments

`object` | Target Object
`...` | Optional parameters (currently ignored)

### Details

Calculate the number of observations in `object`.

- For numeric vectors, this is simply the number of non-NA elements, as computed by `sum(!is.na(object))`.

- For dataframe objects, the result is a vector containing the number of non-NA elementes of each column.

The `nobs` and `nobs.lm` functions defined in gtools are simply aliases for the functions in the base R `stats` package, provided for backwards compatibility.

### Value

Either single numeric value (for vectors) or a vector of numeric values (for data.frames) giving the number of non-missing values.

### Note

The base R package `stats` now provides a S3 dispatch function for `nobs`, and methods for for objects of classes "lm", "glm", "nls" and "logLik", as well as a default method.

Since they provided a subset of the the functionality, the base method dispatch (`nobs`) function and method for "lm" objects (`nobs.lm`) are, as of `gdata` version 2.10.1, simply aliases for the equivalent functions in the base R `stats` package.

Since `gdata`'s default method (`nobs.default`) processes vectors and hands any other data/object types to `stats:::nobs.default`.

### Author(s)

Gregory R. Warnes greg@warnes.net

### See Also

`is.na`, `length`

### Examples

    x <- c(1,2,3,5,NA,6,7,1,NA )
    length(x)
    nobs(x)

    df <- data.frame(x=rnorm(100), y=rnorm(100))
    df[1,1] <- NA
    df[1,2] <- NA
    df[2,1] <- NA

    nobs(df)

    fit <- lm(y ~ x, data=df)
    nobs(fit)

[Package gdata version 2.18.0 Index]