dplyr provides cumall()
, cumany()
, and cummean()
to complete R's set
of cumulative functions.
Arguments
- x
For
cumall()
andcumany()
, a logical vector; forcummean()
an integer or numeric vector.
Cumulative logical functions
These are particularly useful in conjunction with filter()
:
cumall(x)
: all cases until the firstFALSE
.cumall(!x)
: all cases until the firstTRUE
.cumany(x)
: all cases after the firstTRUE
.cumany(!x)
: all cases after the firstFALSE
.
Examples
# `cummean()` returns a numeric/integer vector of the same length
# as the input vector.
x <- c(1, 3, 5, 2, 2)
cummean(x)
#> [1] 1.00 2.00 3.00 2.75 2.60
cumsum(x) / seq_along(x)
#> [1] 1.00 2.00 3.00 2.75 2.60
# `cumall()` and `cumany()` return logicals
cumall(x < 5)
#> [1] TRUE TRUE FALSE FALSE FALSE
cumany(x == 3)
#> [1] FALSE TRUE TRUE TRUE TRUE
# `cumall()` vs. `cumany()`
df <- data.frame(
date = as.Date("2020-01-01") + 0:6,
balance = c(100, 50, 25, -25, -50, 30, 120)
)
# all rows after first overdraft
df %>% filter(cumany(balance < 0))
#> date balance
#> 1 2020-01-04 -25
#> 2 2020-01-05 -50
#> 3 2020-01-06 30
#> 4 2020-01-07 120
# all rows until first overdraft
df %>% filter(cumall(!(balance < 0)))
#> date balance
#> 1 2020-01-01 100
#> 2 2020-01-02 50
#> 3 2020-01-03 25