Matlab等同于Python的“无". [英] The Matlab equivalent of Python's "None"

问题描述

Matlab中是否有一个关键字与python中的None大致相同?

Is there a keyword in Matlab that is roughly equivalent to None in python?

我正在尝试使用它来标记函数的可选参数.我正在翻译以下Python代码

I am trying to use it to mark an optional argument to a function. I am translating the following Python code

def f(x,y=None):
    if y == None:
        return g(x)
    else:
        return h(x,y)

进入Matlab

function rtrn = f(x,y)
    if y == []:
        rtrn = g(x);
    else
        rtrn = h(x,y);
    end;
end

如您所见，当前我正在将[]用作None.有更好的方法吗?

As you can see currently I am using [] as None. Is there a better way to do this?

推荐答案

在您的特定情况下.您可以使用nargin确定在调用函数时此处提供了多少个输入参数.

in your specific case. you may use nargin to determine how many input arguments here provided when calling the function.

摘自 MATLAB文档:

nargin和nargout函数 使您能够确定有多少输入 并输出一个函数的参数 叫.然后，您可以使用 要执行的条件语句 根据不同的任务 参数数量.例如，

The nargin and nargout functions enable you to determine how many input and output arguments a function is called with. You can then use conditional statements to perform different tasks depending on the number of arguments. For example,

function c = testarg1(a, b) 
     if (nargin == 1)
         c = a .^ 2; 
     elseif (nargin == 2)
         c = a + b; 
     end

给出一个输入参数，这个 函数平方输入值. 给定两个输入，它将它们相加 在一起.

Given a single input argument, this function squares the input value. Given two inputs, it adds them together.

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