在Julia中显示函数的所有方法 [英] Show all methods of a function in Julia

问题描述

如何在Julia中显示所有功能的方法(多次派发)?

How can I show all the methods of a function in Julia (multiple dispatch)?

例如，函数abs的命名空间中存在的所有方法.

For example, all the methods that exist in the namespace for the function abs.

推荐答案

方法给定功能的表格:

julia> methods(abs)
# 13 methods for generic function "abs":
[1] abs(a::Pkg.Resolve.FieldValue) in Pkg.Resolve at /home/david/pkg/julia-bin/julia-1.4.0-rc1/share/julia/stdlib/v1.4/Pkg/src/Resolve/fieldvalues.jl:61
[2] abs(a::Pkg.Resolve.VersionWeight) in Pkg.Resolve at /home/david/pkg/julia-bin/julia-1.4.0-rc1/share/julia/stdlib/v1.4/Pkg/src/Resolve/versionweights.jl:36
[3] abs(::Missing) in Base at missing.jl:100
[4] abs(x::Float64) in Base at float.jl:528
...

从Julia 1.4开始，您可以按模块过滤方法表.例如，列出Dates模块中定义的abs方法:

As of Julia 1.4, you can filter the method table by module. For example, listing the methods of abs which were defined in the Dates module:

julia> methods(abs, Dates)
# 1 method for generic function "abs":
[1] abs(a::T) where T<:Dates.Period in Dates at /home/david/pkg/julia-bin/julia-1.4.0-rc1/share/julia/stdlib/v1.4/Dates/src/periods.jl:95

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