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RFC: searchsorted new keyword argument arrayby #35418

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90faf13
searchsorted new keyword argument `arrayby`
KlausC Apr 9, 2020
e351786
fixed documentation
KlausC Apr 10, 2020
0ca07b3
Merge branch 'master' into krc/searchsorted
KlausC May 4, 2020
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2 changes: 2 additions & 0 deletions NEWS.md
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Original file line number Diff line number Diff line change
Expand Up @@ -3,6 +3,8 @@ Julia v1.5 Release Notes

New language features
---------------------
* Functions `searchsorted*` have a new keyword argument `arrayby`, which is applied
to the array, but not to the comparison argument (in constrast to `by`) ([#9429])
* Macro calls `@foo {...}` can now also be written `@foo{...}` (without the space) ([#34498]).
* `⨟` is now parsed as a binary operator with times precedence. It can be entered in the REPL
with `\bbsemi` followed by <kbd>TAB</kbd> ([#34722]).
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83 changes: 49 additions & 34 deletions base/sort.jl
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Expand Up @@ -174,13 +174,13 @@ midpoint(lo::Integer, hi::Integer) = midpoint(promote(lo, hi)...)

# index of the first value of vector a that is greater than or equal to x;
# returns length(v)+1 if x is greater than all values in v.
function searchsortedfirst(v::AbstractVector, x, lo::T, hi::T, o::Ordering)::keytype(v) where T<:Integer
function searchsortedfirst(v::AbstractVector, x, lo::T, hi::T, o::Ordering, aby=identity)::keytype(v) where T<:Integer
u = T(1)
lo = lo - u
hi = hi + u
@inbounds while lo < hi - u
m = midpoint(lo, hi)
if lt(o, v[m], x)
if lt(o, aby(v[m]), x)
lo = m
else
hi = m
Expand All @@ -191,13 +191,13 @@ end

# index of the last value of vector a that is less than or equal to x;
# returns 0 if x is less than all values of v.
function searchsortedlast(v::AbstractVector, x, lo::T, hi::T, o::Ordering)::keytype(v) where T<:Integer
function searchsortedlast(v::AbstractVector, x, lo::T, hi::T, o::Ordering, aby=identity)::keytype(v) where T<:Integer
u = T(1)
lo = lo - u
hi = hi + u
@inbounds while lo < hi - u
m = midpoint(lo, hi)
if lt(o, x, v[m])
if lt(o, x, aby(v[m]))
hi = m
else
lo = m
Expand All @@ -209,26 +209,27 @@ end
# returns the range of indices of v equal to x
# if v does not contain x, returns a 0-length range
# indicating the insertion point of x
function searchsorted(v::AbstractVector, x, ilo::T, ihi::T, o::Ordering)::UnitRange{keytype(v)} where T<:Integer
function searchsorted(v::AbstractVector, x, ilo::T, ihi::T, o::Ordering, aby=identity)::UnitRange{keytype(v)} where T<:Integer
u = T(1)
lo = ilo - u
hi = ihi + u
@inbounds while lo < hi - u
m = midpoint(lo, hi)
if lt(o, v[m], x)
vm = aby(v[m])
if lt(o, vm, x)
lo = m
elseif lt(o, x, v[m])
elseif lt(o, x, vm)
hi = m
else
a = searchsortedfirst(v, x, max(lo,ilo), m, o)
b = searchsortedlast(v, x, m, min(hi,ihi), o)
a = searchsortedfirst(v, x, max(lo,ilo), m, o, aby)
b = searchsortedlast(v, x, m, min(hi,ihi), o, aby)
return a : b
end
end
return (lo + 1) : (hi - 1)
end

function searchsortedlast(a::AbstractRange{<:Real}, x::Real, o::DirectOrdering)::keytype(a)
function searchsortedlast(a::AbstractRange{<:Real}, x::Real, o::DirectOrdering, ::typeof(identity))::keytype(a)
require_one_based_indexing(a)
if step(a) == 0
lt(o, x, first(a)) ? 0 : length(a)
Expand All @@ -238,7 +239,7 @@ function searchsortedlast(a::AbstractRange{<:Real}, x::Real, o::DirectOrdering):
end
end

function searchsortedfirst(a::AbstractRange{<:Real}, x::Real, o::DirectOrdering)::keytype(a)
function searchsortedfirst(a::AbstractRange{<:Real}, x::Real, o::DirectOrdering, ::typeof(identity))::keytype(a)
require_one_based_indexing(a)
if step(a) == 0
lt(o, first(a), x) ? length(a) + 1 : 1
Expand All @@ -248,7 +249,7 @@ function searchsortedfirst(a::AbstractRange{<:Real}, x::Real, o::DirectOrdering)
end
end

function searchsortedlast(a::AbstractRange{<:Integer}, x::Real, o::DirectOrdering)::keytype(a)
function searchsortedlast(a::AbstractRange{<:Integer}, x::Real, o::DirectOrdering, ::typeof(identity))::keytype(a)
require_one_based_indexing(a)
h = step(a)
if h == 0
Expand All @@ -270,7 +271,7 @@ function searchsortedlast(a::AbstractRange{<:Integer}, x::Real, o::DirectOrderin
end
end

function searchsortedfirst(a::AbstractRange{<:Integer}, x::Real, o::DirectOrdering)::keytype(a)
function searchsortedfirst(a::AbstractRange{<:Integer}, x::Real, o::DirectOrdering, ::typeof(identity))::keytype(a)
require_one_based_indexing(a)
h = step(a)
if h == 0
Expand All @@ -292,7 +293,7 @@ function searchsortedfirst(a::AbstractRange{<:Integer}, x::Real, o::DirectOrderi
end
end

function searchsortedfirst(a::AbstractRange{<:Integer}, x::Unsigned, o::DirectOrdering)::keytype(a)
function searchsortedfirst(a::AbstractRange{<:Integer}, x::Unsigned, o::DirectOrdering, ::typeof(identity))::keytype(a)
require_one_based_indexing(a)
if lt(o, first(a), x)
if step(a) == 0
Expand All @@ -305,7 +306,7 @@ function searchsortedfirst(a::AbstractRange{<:Integer}, x::Unsigned, o::DirectOr
end
end

function searchsortedlast(a::AbstractRange{<:Integer}, x::Unsigned, o::DirectOrdering)::keytype(a)
function searchsortedlast(a::AbstractRange{<:Integer}, x::Unsigned, o::DirectOrdering, ::typeof(identity))::keytype(a)
require_one_based_indexing(a)
if lt(o, x, first(a))
0
Expand All @@ -316,25 +317,33 @@ function searchsortedlast(a::AbstractRange{<:Integer}, x::Unsigned, o::DirectOrd
end
end

searchsorted(a::AbstractRange{<:Real}, x::Real, o::DirectOrdering) =
searchsortedfirst(a, x, o) : searchsortedlast(a, x, o)
searchsorted(a::AbstractRange{<:Real}, x::Real, o::DirectOrdering, aby) =
searchsortedfirst(a, x, o, aby) : searchsortedlast(a, x, o, aby)

for s in [:searchsortedfirst, :searchsortedlast, :searchsorted]
@eval begin
$s(v::AbstractVector, x, o::Ordering) = (inds = axes(v, 1); $s(v,x,first(inds),last(inds),o))
$s(v::AbstractVector, x;
lt=isless, by=identity, rev::Union{Bool,Nothing}=nothing, order::Ordering=Forward) =
$s(v,x,ord(lt,by,rev,order))
$s(v::AbstractVector, x, o::Ordering, xform=identity) = (inds = axes(v, 1); $s(v,x,first(inds),last(inds),o, xform))
function $s(v::AbstractVector, x;
lt=isless, by=identity, arrayby=identity, rev::Union{Bool,Nothing}=nothing, order::Ordering=Forward)
if by !== identity && arrayby !== identity
throw(ArgumentError("only one of keyword arguments 'by' and 'arrayby' allowed"))
end
$s(v,x,ord(lt,by,rev,order), arrayby)
end
end
end

"""
searchsorted(a, x; by=<transform>, lt=<comparison>, rev=false)
searchsorted(a, x; {by|arrayby}=<transform>, lt=<comparison>, rev=false)

Return the range of indices of `a` which yield `x <= arrayby(a[i]) <= x`
(using binary search)
according to the order specified by the `by`, `lt` and `rev` keywords,
assuming that `arrayby.(a)` is already sorted in that order.
Only one of `by` and `arrayby` may be different from the default value `identity`.

Return the range of indices of `a` which compare as equal to `x` (using binary search)
according to the order specified by the `by`, `lt` and `rev` keywords, assuming that `a`
is already sorted in that order. Return an empty range located at the insertion point
if `a` does not contain values equal to `x`.
Return an empty range located at the insertion point
if `arrayby.(by.(a))` does not contain values equal to `by(x)`.

# Examples
```jldoctest
Expand All @@ -356,11 +365,14 @@ julia> searchsorted([1, 2, 4, 5, 5, 7], 0) # no match, insert at start
""" searchsorted

"""
searchsortedfirst(a, x; by=<transform>, lt=<comparison>, rev=false)
searchsortedfirst(a, x; {by|arrayby}=<transform>, lt=<comparison>, rev=false)

Return the index of the first value in `a` greater than or equal to `x`, according to the
specified order. Return `length(a) + 1` if `x` is greater than all values in `a`.
`a` is assumed to be sorted.
Return the index of the first value in `a` greater than or equal to `x`,
according to the order specified by the `by`, `lt` and `rev` keywords,
assuming that `arrayby.(a)` is already sorted in that order.
Only one of `by` and `arrayby` may be different from the default value `identity`.

Return `length(a) + 1` if `x` is greater than all values in `arrayby.(a)`.

# Examples
```jldoctest
Expand All @@ -382,11 +394,14 @@ julia> searchsortedfirst([1, 2, 4, 5, 5, 7], 0) # no match, insert at start
""" searchsortedfirst

"""
searchsortedlast(a, x; by=<transform>, lt=<comparison>, rev=false)
searchsortedlast(a, x; {by|arrayby}=<transform>, lt=<comparison>, rev=false)

Return the index of the last value in `a` less than or equal to `x`,
according to the order specified by the `by`, `lt` and `rev` keywords,
assuming that `arrayby.(a)` is already sorted in that order.
Only one of `by` and `arrayby` may be different from the default value `identity`.

Return the index of the last value in `a` less than or equal to `x`, according to the
specified order. Return `0` if `x` is less than all values in `a`. `a` is assumed to
be sorted.
Return `0` if `x` is less than all values in `arrayby.(a)`.

# Examples
```jldoctest
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10 changes: 10 additions & 0 deletions test/sorting.jl
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Expand Up @@ -201,6 +201,16 @@ end
@test searchsorted(v, 0.1, rev=true) === 4:3
end
end

@testset "issue #9429" begin
@test_throws ArgumentError searchsortedfirst(1:10, 24, by=i->i^2, arrayby=i->i)
@test searchsortedfirst(1:10, 24, by=i->i^2) == 11
@test searchsortedfirst(1:10, 24, arrayby=i->i^2) == 5
@test searchsortedlast(1:10, 24, by=i->i^2) == 10
@test searchsortedlast(1:10, 24, arrayby=i->i^2) == 4
@test searchsorted(1:10, 25, by=i->i^2) == 11:10
@test searchsorted(1:10, 25, arrayby=i->i^2) == 5:5
end
end
# exercise the codepath in searchsorted* methods for ranges that check for zero step range
struct ConstantRange{T} <: AbstractRange{T}
Expand Down