sample-methods memisc 0.99.22

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
32           5.4         3.4          1.5         0.4     setosa
142          6.9         3.1          5.1         2.3  virginica
112          6.4         2.7          5.3         1.9  virginica
78           6.7         3.0          5.0         1.7 versicolor
140          6.9         3.1          5.4         2.1  virginica
    Sepal.Length Sepal.Width Petal.Length Petal.Width    Species
146          6.7         3.0          5.2         2.3  virginica
15           5.8         4.0          1.2         0.2     setosa
31           4.8         3.1          1.6         0.2     setosa
85           5.4         3.0          4.5         1.5 versicolor
87           6.7         3.1          4.7         1.5 versicolor
    Sepal.Length Sepal.Width Petal.Length Petal.Width    Species
74           6.1         2.8          4.7         1.2 versicolor
24           5.1         3.3          1.7         0.5     setosa
102          5.8         2.7          5.1         1.9  virginica
33           5.2         4.1          1.5         0.1     setosa
122          5.6         2.8          4.9         2.0  virginica
    Sepal.Length Sepal.Width Petal.Length Petal.Width    Species
76           6.6         3.0          4.4         1.4 versicolor
40           5.1         3.4          1.5         0.2     setosa
124          6.3         2.7          4.9         1.8  virginica
65           5.6         2.9          3.6         1.3 versicolor
32           5.4         3.4          1.5         0.4     setosa