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Converting between integer types #22235

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Converting between integer types #22235

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25fa6f1
Two argument version of clamp and clamp!
arghhhh Jun 6, 2017
4a59f65
Removed whitespace
arghhhh Jun 6, 2017
27d9634
Removed clamp\!, removed whitespace
arghhhh Jun 6, 2017
ed37037
Fix docs
ararslan Jun 6, 2017
6efde61
Merge branch 'master' of github.com:JuliaLang/julia into clamp2arg
arghhhh Jun 7, 2017
fcd526e
Separated docs for new clamp, restricted T<:Integer
arghhhh Jun 7, 2017
9a8a73c
Resolved conflict.. in clamp docstring
arghhhh Jun 7, 2017
2243307
Removed clamp! from doc string
arghhhh Jun 8, 2017
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5 changes: 4 additions & 1 deletion base/math.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -41,9 +41,11 @@ end

"""
clamp(x, lo, hi)
clamp(T, x)
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@fredrikekre fredrikekre Jun 7, 2017 •
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I think that this would be more clear (i.e. more distinct) with two separate docstrings instead of trying to explain two things in the same docstring.
Something like:

"""
    clamp(T, x)

Clamp `x` between `typemin(T)` and `typemax(T)` and convert the result to type `T`.

```jldoctest
julia> clamp(Int8, 200)
127

julia> clamp(Int8, -200)
-128
```
"""


Return `x` if `lo <= x <= hi`. If `x < lo`, return `lo`. If `x > hi`, return `hi`. Arguments
are promoted to a common type.
are promoted to a common type. If a type `T` is given, `lo` and `hi` are `typemin(T)`
and `typemax(T)` respectively, and the result is converted to `T`.

```jldoctest
julia> clamp.([pi, 1.0, big(10.)], 2., 9.)
Expand All @@ -59,6 +61,7 @@ clamp(x::X, lo::L, hi::H) where {X,L,H} =
convert(promote_type(X,L,H), lo),
convert(promote_type(X,L,H), x)))

clamp(::Type{T}, x) where {T} = clamp(x, typemin(T), typemax(T)) % T
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Maybe where {T<:Integer} ?

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Yes. It doesn't make sense for floats - the % operator isn't defined, and the problem doesn't exist because conversion to a narrower float clamps to typemin and typemax (+/-Inf) anyway.

"""
clamp!(array::AbstractArray, lo, hi)

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5 changes: 5 additions & 0 deletions test/math.jl
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Expand Up @@ -15,6 +15,11 @@

@test clamp.([0, 1, 2, 3, 4], 1.0, 3.0) == [1.0, 1.0, 2.0, 3.0, 3.0]
@test clamp.([0 1; 2 3], 1.0, 3.0) == [1.0 1.0; 2.0 3.0]

@test clamp(Int8,-200) === typemin(Int8)
@test clamp(Int8,100) === Int8(100)
@test clamp(Int8,200) === typemax(Int8)

begin
x = [0.0, 1.0, 2.0, 3.0, 4.0]
clamp!(x, 1, 3)
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