# A very quick question

3 views (last 30 days)
Radoslav Gagov on 12 Apr 2017
Commented: Radoslav Gagov on 12 Apr 2017
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.
##### 2 CommentsShowHide 1 older comment
Radoslav Gagov on 12 Apr 2017
Normally they are numeric or logical

Sign in to comment.

### Answers (2)

David J. Mack on 12 Apr 2017
Edited: David J. Mack on 12 Apr 2017
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
##### 0 CommentsShowHide -1 older comments

Sign in to comment.

Andrei Bobrov on 12 Apr 2017
Edited: Andrei Bobrov on 12 Apr 2017
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);
##### 2 CommentsShowHide 1 older comment
Radoslav Gagov on 12 Apr 2017
O yes i found out why. U are transforming the chars in to numbers, but i still dont get it what does - '0' does.

Sign in to comment.

### Categories

Find more on Matrix Indexing in Help Center and File Exchange

### Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!