sample-methods memisc 0.99.20.1

Take a Sample from a Data Frame-like Object

Description

The methods below are convenience short-cuts to take samples from data frames and data sets. They result in a data frame or data set, respectively, the rows of which are a sample of the complete data frame/data set.

Usage

## S4 method for signature 'data.frame'
sample(x, size, replace = FALSE, prob = NULL)
## S4 method for signature 'data.set'
sample(x, size, replace = FALSE, prob = NULL)
## S4 method for signature 'importer'
sample(x, size, replace = FALSE, prob = NULL)

Arguments

x

a data frame or data set.

size

an (optional) numerical value, the sample size, defaults to the total number of rows of x.

replace

a logical value, determines whether sampling takes place with or without replacement.

prob

a vector of sampling probabities or NULL.

Value

A data frame or data set.

Examples

for(.i in 1:4)
 print(sample(iris,5))
   Sepal.Length Sepal.Width Petal.Length Petal.Width    Species
14          4.3         3.0          1.1         0.1     setosa
86          6.0         3.4          4.5         1.6 versicolor
4           4.6         3.1          1.5         0.2     setosa
22          5.1         3.7          1.5         0.4     setosa
47          5.1         3.8          1.6         0.2     setosa
    Sepal.Length Sepal.Width Petal.Length Petal.Width    Species
50           5.0         3.3          1.4         0.2     setosa
85           5.4         3.0          4.5         1.5 versicolor
54           5.5         2.3          4.0         1.3 versicolor
123          7.7         2.8          6.7         2.0  virginica
104          6.3         2.9          5.6         1.8  virginica
   Sepal.Length Sepal.Width Petal.Length Petal.Width    Species
68          5.8         2.7          4.1         1.0 versicolor
64          6.1         2.9          4.7         1.4 versicolor
32          5.4         3.4          1.5         0.4     setosa
16          5.7         4.4          1.5         0.4     setosa
71          5.9         3.2          4.8         1.8 versicolor
    Sepal.Length Sepal.Width Petal.Length Petal.Width    Species
64           6.1         2.9          4.7         1.4 versicolor
142          6.9         3.1          5.1         2.3  virginica
37           5.5         3.5          1.3         0.2     setosa
94           5.0         2.3          3.3         1.0 versicolor
17           5.4         3.9          1.3         0.4     setosa