Functions: ans at end...where it is coming from?

Question

Anna 2013-7-27

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/83342-functions-ans-at-end-where-it-is-coming-from

In entering the following function:

    function [ft,in] = MetricToImperial(m)
  % Input: m = measurement in metres
  % Outputs: ft = number of feet
  %          in = number of inches
m = 2;
% Calculate the total number of cms
cm = m * 100;
% Calculate the total number of inches
totalInches = cm/2.54;
% Calculate the total number of feet, ignoring the value after decimal
ft = floor(totalInches/12)
% Find the remaining number of inches
in = totalInches - 12*ft
   return

When running the function matlab returns:

EDU>> MetricToImperial
ft =
       6
in =
      6.7402
  ans =
6

Now i was wondering why I get the ans = 6 at the end. All i want is the ft and in answer. I have tested it as a script and it works that way so I know it must be something to do with my inputs and outputs.

I have also noticed if I leave line 1 as

function [] = MetricToImperial(m)

it gives me the result I want - so something is wrong as I'm saying there's no output variables but there is.

Is this the correct way to create a function? I am very new to this so any help is appreciated.

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

kjetil87 2013-7-28

3
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/83342-functions-ans-at-end-where-it-is-coming-from#answer_92961

在 MATLAB Online 中打开

It is because you are typing:

>> MetricToImperial

and nothing more. Since your are not assigning MetricToImperial output to anything, and neither supressing the function in the matlab command line, the first output "in" will be returned as

ans

where ans in this case is the answer from your function.

Try this if it is not yet clear:

>> [out1,out2]=MetricToImperial
>> [out1,out2]=MetricToImperial;
>> MetricToImperial;
>> out1=MetricToImperial

The frist will return

while number two will write nothing in the command window but it will assign the outputs out1 and out2.

etc

So the ans=6 is not random at all, it is the returned value from your function.

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

Answer 2

Honglei Chen 2013-7-27

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/83342-functions-ans-at-end-where-it-is-coming-from#answer_92912

在 MATLAB Online 中打开

The first two answer you get is due to the fact you didn't end the corresponding lines in your function with semi-colon. The ans is populated because your function has an output but the output is not specified when you invoke the function. You should add semi-colon behind both lines and invoke the function as

[ft,in] = MetricToImperial

Finally your input, m, does not seem to be used at all.

3 个评论
显示 1更早的评论隐藏 1更早的评论

Walter Roberson 2013-7-27

You might intend it as your input, but you are assigning it in the function, making it useless to pass it as your input. You probably should not be assigning it in your function.

Anna 2013-7-27