## how to find the number of 1 in a single column?

Asked by Sivakumaran Chandrasekaran

### Sivakumaran Chandrasekaran (view profile)

on 5 Sep 2012

My input is

0 0 0 0 1 0 0 1 1 0 0 0 1 0

I should find how many 1 is present

Azzi Abdelmalek

on 5 Sep 2012

is it a string ?

Azzi Abdelmalek

### Azzi Abdelmalek (view profile)

on 5 Sep 2012

what is the real question?

### Jan Simon (view profile)

Answer by Jan Simon

### Jan Simon (view profile)

on 5 Sep 2012
Edited by Jan Simon

### Jan Simon (view profile)

on 5 Sep 2012

If it is a string:

```c = '0 0 0 0 1 0 0 1 1 0 0 0 1 0';
s = sum(c == '1');
% or:
s = length(strfind(c, '1');
```

if it is a numeric vector:

```c = [0 0 0 0 1 0 0 1 1 0 0 0 1 0];
s = sum(c);  % as Jose-Luis has suggested already
% or:
s = nnz(c);
```

### José-Luis (view profile)

on 5 Sep 2012
Edited by José-Luis

### José-Luis (view profile)

on 5 Sep 2012

```your_answer = sum(your_input)
```

### Azzi Abdelmalek (view profile)

Answer by Azzi Abdelmalek

### Azzi Abdelmalek (view profile)

on 5 Sep 2012

``` c='0 0 0 0 1 0 0 1 1 0 0 0 1 0'
sum(str2num(c))```

### Sivakumaran Chandrasekaran (view profile)

Answer by Sivakumaran Chandrasekaran

### Sivakumaran Chandrasekaran (view profile)

on 5 Sep 2012

Thanks for all replies...

1 1

```     1     2
3     1
2     1
3     1
1     2
3     2
2     1
3     1
2     1
3     2
2     2
3     1
2     2```

### Sivakumaran Chandrasekaran (view profile)

Answer by Sivakumaran Chandrasekaran

### Sivakumaran Chandrasekaran (view profile)

on 5 Sep 2012

thats my input matrix.. let me take query input as 1 1... now i have to check this 1 1 with all the rows of the given input matrix.. I have find the rows which matches this input.

Sivakumaran Chandrasekaran

### Sivakumaran Chandrasekaran (view profile)

on 5 Sep 2012

when i take the first row as the query one, and if i found it is matching with 5th, then output should be displayed as [1,5]

José-Luis

### José-Luis (view profile)

on 5 Sep 2012
```your_result = find(ismember(your_matrix,[1 2],'rows'))';
```

### Matt Tearle (view profile)

Answer by Matt Tearle

### Matt Tearle (view profile)

on 5 Sep 2012
Edited by Matt Tearle

### Matt Tearle (view profile)

on 5 Sep 2012

```idx = find(all(bsxfun(@eq,x,y),2));
```

where x is your matrix and y is your test vector (eg y = x(1,:), in your example). For example

```x = randi(4,1000,5);
y = x(3,:);
idx = find(all(bsxfun(@eq,x,y),2))
```

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