减法中没有方法匹配 [英] no method matching in subtraction

问题描述

运行此代码后，我正在使用julia 0.5:

I'm using julia 0.5 after run this code :

Freqsample = 100;
second = 4;
step = (Freqsample * second )-1

我收到此错误:

MethodError: no method matching getindex(::Int64, ::Colon, ::UnitRange{Int64})
 in -(::Int64, ::Int64) at main.jl:12
 in include_string(::String, ::String) at loading.jl:441
 in eval(::Module, ::Any) at boot.jl:234
 in (::Atom.##65#68)() at eval.jl:40
 in withpath(::Atom.##65#68, ::Void) at utils.jl:30
 in withpath(::Function, ::Void) at eval.jl:46
 in macro expansion at eval.jl:109 [inlined]
 in (::Atom.##64#67{Dict{String,Any}})() at task.jl:60

减法有什么问题?我对朱莉娅(Julia)很陌生，请问这是一个愚蠢的问题

Whats wrong with subtracting ? i'm pretty new to julia forgive if its a dumb question

推荐答案

您已经重新定义了-，以获取比预期更多的类型.您发布的回溯中的第二行告诉您Julia在main.jl中为两个整数调用了-方法.第一行说在那儿，它试图在第12行做类似x[:, 1:5]的事情，其中​​x是一个整数.

You've redefined - for more types than you probably intended. The second line in the backtrace you posted is telling you that Julia called a - method in main.jl for two integers. And line one is saying that within there it's trying to do something like x[:, 1:5] at line 12, where x is an integer.

这告诉我两件事；

1. 您对-的定义键入的内容可能过于宽松.您可能不打算接受整数.

1. Your definition of - is probably typed too permissively. You probably didn't intend to accept integers.

您可能正在 shadowing 内置的-定义，而不是对其进行扩展.您需要import Base: -才能向标准库中的函数添加新方法.

You are probably shadowing the built in - definition instead of extending it. You need to import Base: - in order to add a new method to a function in the standard library.

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