MATLAB Central Newsreader - sorting and finding the position

sorting and finding the position

shanas pr — Sun, 27 Nov 2011 17:34:08 +0000

pls help me

I have a series of data with 5 columns and 100 rows

what i wan to do is .....to find the maximum value of a specific column let us say 5th column and to print the entire row which contain the maximum value (at column 5)????

and to repeat the procedure for1000s of rows plz do help

for example>>>>>

                                    1 2 3 4
                                    6 4 5 9
                                    2 6 8 0

i want to check which is the max value in 4th column? answer will be 9
then i need to print the 2nd row ie.6 4 5 9???

thanks in advance...

Re: sorting and finding the position

Rune Allnor — Sun, 27 Nov 2011 17:38:30 +0000

On 27 Nov, 18:34, "shanas pr" <shana...@gmail.com> wrote:
> pls help me
>
> I have a series of data with 5 columns and 100 rows
>
> what i wan to do is .....to find the maximum value of a specific column let us say 5th column and to print the entire row which contain the maximum value (at column 5)????
>
> and to repeat the procedure for1000s of rows plz do help
>
> for example>>>>>
>
> 1 2 3 4
> 6 4 5 9
> 2 6 8 0
>
> i want to check which is the max value in 4th column? answer will be 9
> then i need to print the 2nd row ie.6 4 5 9???
>
> thanks in advance...

idx = find (x(:,4)==max(:,4));
x(idx,:)

Rune

Re: sorting and finding the position

Nasser M. Abbasi — Sun, 27 Nov 2011 18:23:57 +0000

On 11/27/2011 11:38 AM, Rune Allnor wrote:
> On 27 Nov, 18:34, "shanas pr"<shana...@gmail.com> wrote:
>> pls help me
>>
>> I have a series of data with 5 columns and 100 rows
>>
>> what i wan to do is .....to find the maximum value of a specific column let us
>say 5th column and to print the entire row which contain the maximum value (at column 5)????
>>
>> and to repeat the procedure for1000s of rows plz do help
>>
>> for example>>>>>
>>
>> 1 2 3 4
>> 6 4 5 9
>> 2 6 8 0
>>
>> i want to check which is the max value in 4th column? answer will be 9
>> then i need to print the 2nd row ie.6 4 5 9???
>>
>> thanks in advance...
>

> idx = find (x(:,4)==max(:,4));
> x(idx,:)
>
> Rune

another possibility is the use of the second output
argument to max:

----------------------
[v,I]=max(A(:,4))
A(I,:)

ans =

6 4 5 9

---------------------

--Nasser

Re: sorting and finding the position

Roger Stafford — Sun, 27 Nov 2011 18:27:08 +0000

"shanas pr" <shanaspr@gmail.com> wrote in message <jatsag$q6d$1@newscl01ah.mathworks.com>...
> I have a series of data with 5 columns and 100 rows
> what i wan to do is .....to find the maximum value of a specific column let us say 5th column and to print the entire row which contain the maximum value (at column 5)????
> and to repeat the procedure for1000s of rows plz do help
- - - - - - - -
Let c be a vector containing column numbers to be tested and A the data matrix in question.

[~,p] = max(A(:,c),1);
x(p,:) % <--- Or use fprintf to print these

Roger Stafford

Re: sorting and finding the position

Roger Stafford — Sun, 27 Nov 2011 18:40:09 +0000

"Roger Stafford" wrote in message <jatvds$5fb$1@newscl01ah.mathworks.com>...
> [~,p] = max(A(:,c),1);
> x(p,:) % <--- Or use fprintf to print these
- - - - - - - -
Whoops!

[~,p] = max(A(:,c),1);
A(p,:) % <--- Or use fprintf to print these

Roger Stafford