How to use exist for a cell?

Question

osminbas 2012-4-12

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/35299-how-to-use-exist-for-a-cell

Hello,

I have a cell with string elements and I am trying to check if they exist as variables:

A={'B0','B01','B04'}
for i=1:3
if exist(A(i,1),'var')==1
...

This does not work so what do I do? Thx!

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

Walter Roberson 2012-4-12

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/35299-how-to-use-exist-for-a-cell#answer_44237

在 MATLAB Online 中打开

if exist(A{i,1},'var')

Notice the {} instead of ()

3 个评论
显示 1更早的评论隐藏 1更早的评论

Shamir Alavi 2012-12-7

在 MATLAB Online 中打开

It doesn't work for me! Here's the code:

>> h = {1,2;3,4};

>> exist('h','var')

ans =

1

>> exist('h{1}','var')

ans =

0

>> exist('h{1,1}','var')

ans =

0

Am I making any mistake? If not, is there any other way to check existence of different elements in a cell array?

Thanks

Matt J 2012-12-7

编辑：Matt J 2012-12-7

You have several errors. First, notice that Walter doesn't enclose the first argument to exist() in quotes. Secondly, your h{i,j} data are not relevant examples because they are not strings.

请先登录，再进行评论。

Answer 2

RNTL 2012-4-12

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/35299-how-to-use-exist-for-a-cell#answer_44232

在 MATLAB Online 中打开

ismember(A,who)

2 个评论
显示无隐藏无

osminbas 2012-4-12

Actually, I am really trying to use exist and check the elements one by one in a loop so ismember(A,who) would not work for me.

Jan 2012-12-7

@osminbas: Please take the time to think twice. This method would help to avoid the loop or at least compare all elements of the cell string h in a very compact form.

请先登录，再进行评论。