# sample

##### Sample n rows from a table

This is a wrapper around `sample.int()`

to make it easy to
select random rows from a table. It currently only works for local
tbls.

##### Usage

`sample_n(tbl, size, replace = FALSE, weight = NULL, .env = NULL)`sample_frac(tbl, size = 1, replace = FALSE, weight = NULL,
.env = NULL)

##### Arguments

- tbl
tbl of data.

- size
For

`sample_n()`

, the number of rows to select. For`sample_frac()`

, the fraction of rows to select. If`tbl`

is grouped,`size`

applies to each group.- replace
Sample with or without replacement?

- weight
Sampling weights. This must evaluate to a vector of non-negative numbers the same length as the input. Weights are automatically standardised to sum to 1.

This argument is automatically quoted and later evaluated in the context of the data frame. It supports unquoting. See

`vignette("programming")`

for an introduction to these concepts.- .env
This variable is deprecated and no longer has any effect. To evaluate

`weight`

in a particular context, you can now unquote a quosure.

##### Examples

```
# NOT RUN {
by_cyl <- mtcars %>% group_by(cyl)
# Sample fixed number per group
sample_n(mtcars, 10)
sample_n(mtcars, 50, replace = TRUE)
sample_n(mtcars, 10, weight = mpg)
sample_n(by_cyl, 3)
sample_n(by_cyl, 10, replace = TRUE)
sample_n(by_cyl, 3, weight = mpg / mean(mpg))
# Sample fixed fraction per group
# Default is to sample all data = randomly resample rows
sample_frac(mtcars)
sample_frac(mtcars, 0.1)
sample_frac(mtcars, 1.5, replace = TRUE)
sample_frac(mtcars, 0.1, weight = 1 / mpg)
sample_frac(by_cyl, 0.2)
sample_frac(by_cyl, 1, replace = TRUE)
# }
```

*Documentation reproduced from package dplyr, version 0.7.8, License: MIT + file LICENSE*