Runs

• vec_identify_runs() returns a vector of identifiers for the elements of x that indicate which run of repeated values they fall in. The number of runs is also returned as an attribute, n.

• vec_run_sizes() returns an integer vector corresponding to the size of each run. This is identical to the times column from vec_unrep(), but is faster if you don't need the run keys.

• vec_unrep() is a generalized base::rle(). It is documented alongside the "repeat" functions of vec_rep() and vec_rep_each(); look there for more information.

Usage

vec_identify_runs(x)

vec_run_sizes(x)

Arguments

x

A vector.

Value

• For vec_identify_runs(), an integer vector with the same size as x. A scalar integer attribute, n, is attached.

• For vec_run_sizes(), an integer vector with size equal to the number of runs in x.

Details

Unlike base::rle(), adjacent missing values are considered identical when constructing runs. For example, vec_identify_runs(c(NA, NA)) will return c(1, 1), not c(1, 2).

See also

vec_unrep() for a generalized base::rle().

Examples

x <- c("a", "z", "z", "c", "a", "a")

vec_identify_runs(x)
#> [1] 1 2 2 3 4 4
#> attr(,"n")
#> [1] 4
vec_run_sizes(x)
#> [1] 1 2 1 2
vec_unrep(x)
#>   key times
#> 1   a     1
#> 2   z     2
#> 3   c     1
#> 4   a     2

y <- c(1, 1, 1, 2, 2, 3)

# With multiple columns, the runs are constructed rowwise
df <- data_frame(
  x = x,
  y = y
)

vec_identify_runs(df)
#> [1] 1 2 2 3 4 5
#> attr(,"n")
#> [1] 5
vec_run_sizes(df)
#> [1] 1 2 1 1 1
vec_unrep(df)
#>   key.x key.y times
#> 1     a     1     1
#> 2     z     1     2
#> 3     c     2     1
#> 4     a     2     1
#> 5     a     3     1