Indexing to create a new array

I have a very simple question, but just can't seem to wrap my brain around the answer today.

My index:

>> Wtr

Wtr =

      12
       1
       2
My data:

mNEE =

    1.0000       NaN
    2.0000       NaN
    3.0000    0.2165
    4.0000    3.9982
    5.0000   18.3253
    6.0000   32.6099
    7.0000   14.7678
    8.0000   36.8627
    9.0000   -1.0730
   10.0000   -8.2807
   11.0000    6.7998
   12.0000   25.0182
    1.0000    8.1078
    2.0000    0.7304
    3.0000   -6.2877
    4.0000   -2.5207
    5.0000   10.5052
    6.0000   11.2116
    7.0000    4.8839
    8.0000   -8.1560
    9.0000  -16.8618
   10.0000  -45.3915
   11.0000  -39.8423
   12.0000   -8.4954
    1.0000   13.1454
    2.0000   31.7136
    3.0000   41.5338
    4.0000   19.9113
    5.0000   18.7724
    6.0000  -20.1884
    7.0000   -7.9781
    8.0000  -12.7571
    9.0000  -21.3081
   10.0000  -18.9930
   11.0000  -31.7573
   12.0000   -7.2601
    1.0000   10.2586
    2.0000   16.4023
    3.0000   45.1588
    4.0000   24.6945
    5.0000    0.0275
    6.0000    7.3914
    7.0000   -3.5258
    8.0000  -15.4096
    9.0000  -19.4229
   10.0000  -21.2903
   11.0000  -11.5092
   12.0000  -55.0183
    1.0000  -53.4840
    2.0000   -4.5846
    3.0000   14.0066
    4.0000    0.5472
    5.0000   31.4220
    6.0000    8.1386
    7.0000  -13.0516
    8.0000   -2.7136
    9.0000       NaN
   10.0000       NaN
   11.0000       NaN
   12.0000       NaN

All that I really want to do is pull data where the 1st column of mNEE==Anything in Wtr.

But when I run this super simple for loop I only get the first 3 matches, when I want all the data that falls within the category of Wtr in a new array:

for i=1:length(mNEE)
      t=mNEE(Wtr,:);
end

>> t

t =

     12.0000   25.0182
      1.0000       NaN
      2.0000       NaN

Could someone please help me understand why Matlab finds the first 3 matches, but not anymore? This seems so simple but is eluding me.

Thanks a million.

Answer 1

[Image Analyst]

Try this:

matchingRows = ismember(mNEE(:,1), Wtr)
extractedRows = mNEE(matchingRows, :)

[Kate]

The wierd thing is that I get an index of all 0's for this:

matchingRows =

       0
       0
       0
       0
       0
       0
       0
       0
       0
       0
       0
       0
       0
       0
       0
       0
       0
       0
       0
       0
       0
       0
       0
       0
       0
       0
       0
       0
       0
       0
       0
       0
       0

[Kate]

And I checked to see if my Matlab was getting cranky, but it can find simple ismembers:

test =

       1
       2
       3
       4
       5
       6
       7
       8
       9
      10

>> t=[2,4,6]'

t =

       2
       4
       6

>> ismember(test, t)

ans =

       0
       1
       0
       1
       0
       1
       0
       0
       0
       0

[Kate]

Nevermind, this works perfectly, thanks :)

Answer 2

[Azzi Abdelmalek]

mNEE =[1.0000  NaN
  2.0000       NaN
  3.0000    0.2165
  4.0000    3.9982
  5.0000   18.3253
  6.0000   32.6099]
wtr=[12;1;2]
idx=ismember(mNEE(:,1),wtr)
mNEE(idx,:)=[]

%or

data=mNEE(~idx,:)

[Kate]

For some reason my idx is pure 0's no "matching" 1's.

[Azzi Abdelmalek]

you did something wrong

[Marc]

And now it begins....

[Azzi Abdelmalek]

What do you mean?

[Marc]

Just that you are RIGHT and Kate is WRONG.... Let it begin