A very quick question

Hello Guys. Can you tell me how can I write a code that is like

 >> [ida,idb] = ismember('1','1 0 0 1')

 ida =
   logical
   1
 idb =
     1
but the outpoot i need is 

 idb =
     [1 4]

I suppose it can be made with a double loop or smth, but I am looking for a simpler way.

[Stephen23]

@Radoslav Gagov: do the inputs have to be strings ? Or can they be numeric?

[Radoslav Gagov]

Normally they are numeric or logical

Answer 1

[David J. Mack]

Hey Radoslav,

In general, to convert a logical array to ids use find.

If you are working on numbers (as implied in your example) try

idb = find(ismember(1,[1 0 0 1])) % No quotes!

If you work on strings, either use a "set" with a cellstr:

idb = find(ismember('1',{'1','0','0','1'}))

Or better, use strfind without the spaces.

str = '1 0 0 1';
idb = strfind('1',str(~isspace(str))); % Remove spaces

Hope that helps.

Greetings, David

Answer 2

[Andrei Bobrov]

A = '1 0 0 1';
B = '1';

An = A - '0';
Bn = B - '0';
An = An(An >= 0);
Bn = Bn(Bn >= 0);

idb = find(Bn == An);

for numeric

idb = find(B == A);

[Radoslav Gagov]

Hmm that works thanks. Can you just explain to me why do we make that An = A - '0'. What does this like actually do ?

[Radoslav Gagov]

O yes i found out why. U are transforming the chars in to numbers, but i still dont get it what does - '0' does.