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Select a Range Between Two Elements

Source: R/range-operators.R
range-operators.Rd

Returns the elements of x from the first occurrence of rng[1] up to an occurrence of rng[2]. The two operators differ in which occurrence of the end value terminates the range, analogous to lazy and greedy quantifiers in regular expressions:

Usage

x %:% rng

x %::% rng

Arguments

x

a vector.

rng

a vector of length 2: c(from, to). May contain NA to match missing values in x.

Value

a subset of x, from the first occurrence of rng[1] to the first (%:%) or last (%::%) occurrence of rng[2].

Details

  • %:% (lazy): up to the first occurrence of rng[2].

  • %::% (greedy): up to the last occurrence of rng[2].

See also

Other data.interval: between-operators, intervals

Examples

letters %:% c("c", "g")
#> [1] "c" "d" "e" "f" "g"

x <- c("a", "b", "c", "d", "c", "e", "f", "c")
x %:%  c("c", "e")
#> [1] "c" "d" "c" "e"
x %::% c("c", "c")     # greedy: up to the last "c"
#> [1] "c" "d" "c" "e" "f" "c"

# select a column range by name
colnames(mtcars) %:% c("hp", "vs")
#> [1] "hp"   "drat" "wt"   "qsec" "vs"