extractors: Extract vectors by index or value occurrence

In FredHasselman/invctr: Infix Functions For Vector Operations

Extract vectors by index or value occurrence

Description

Extract vectors by index or value occurrence

Extract front by first occurrence of a value ⁠%[f%⁠

Extract front by last occurrence of a value ⁠%[l%⁠

Extract vector front by index ⁠%[%⁠

Extract vector rear by index ⁠%]%⁠

Extract first occurrence of a value to vector rear ⁠%f]%⁠

Extract last occurrence of a value to vector rear ⁠%l]%⁠

Extract values at percentile and higher ⁠%q]%⁠

Extract values higher than percentile ⁠%q)%⁠

Extract values at percentile and smaller ⁠%[q%⁠

Extract values smaller than percentile ⁠%(q%⁠

Extract first, middle or last value of vector ⁠%:%⁠

Usage

x %[f% v

x %[l% v

x %[% i

x %]% i

x %f]% v

x %l]% v

x %q]% q

x %q)% q

x %[q% q

x %(q% q

x %:% j

Arguments

x	A vector
v	A value of which the first or last occurrence in x will be used as an index
i	An index or two element vector c(lo,hi) indicating a range to extract
q	A percentile value (between 0 and 1)
j	A character indicating to extract the first f, middle m or last l value of x.

Value

A vector extracted from the front, rear, or, range of x. Either based on an index or the first or last occurrence of a value or the first, middle, or, last element of a vector.

Note

The function provided for symmetry, character lengths of x%]%i and x[1:i] are equal.

Examples

z <- letters

# Extract front by first occurrence of value
z %[f% "n"

# Extract front by index
x <- rnorm(100)
x %[% 10

# Extract rear by index
x %]% 90

# Extract rear by index
x %]% 90

# Extract by indices if a range is provided
x %]% c(4,30)
z %[% c(6,10)

# Extract last/middle value of x
x %:% "l"
z %:% "m"

# Extract by percentile
seq(1,10,.5) %(q% .5 # infix
seq(1,10,.5)[seq(1,10,.5) < quantile(seq(1,10,.5),.5)] # regular syntax

seq(1,10,.5) %q]% .5 # infix
seq(1,10,.5)[seq(1,10,.5) >= quantile(seq(1,10,.5),.5)] # regular syntax

FredHasselman/invctr documentation built on Feb. 19, 2025, 5:12 a.m.