从 R 编程中的数据集生成一组样本数据 – sample()函数

R 语言中的sample()函数根据函数调用中提供的参数创建随机样本。它采用向量或正整数作为函数参数中的对象。

Syntax:
sample(x, size, replace)

Parameters:
x: indicates either vector or a positive integer or data frame
size: indicates size of sample to be taken
replace: indicates logical value. If TRUE, sample may have more than one same value

要了解更多可选参数，请在控制台中使用以下命令：

help("sample")

示例 1：

# Create sample
x <- sample(1:100, 10, replace=TRUE)
  
# Print
# Output may differ each time the command is executed
print(x)

输出：

[1] 47 52 22 98 75 94 91 94 42 53

示例 2：

# Create sample
pos <- sample(1:nrow(mtcars), 5, replace = TRUE)
  
# Print sample observations
# Output may differ each time the command is executed
print(mtcars[pos, ])

输出：

mpg cyl  disp  hp drat    wt  qsec vs am gear carb
Honda Civic      30.4   4  75.7  52 4.93 1.615 18.52  1  1    4    2
Merc 240D        24.4   4 146.7  62 3.69 3.190 20.00  1  0    4    2
Hornet 4 Drive   21.4   6 258.0 110 3.08 3.215 19.44  1  0    3    1
Hornet 4 Drive.1 21.4   6 258.0 110 3.08 3.215 19.44  1  0    3    1
Fiat 128         32.4   4  78.7  66 4.08 2.200 19.47  1  1    4    1