Nested Loop not working

Question

Ping 2012-10-14

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/50776-nested-loop-not-working

The error I am getting is Error using make_nextRow (line 21) Not enough input arguments. but i've rechecked the code and I can't see anything that is wrong

here is the code, and I commented what each line is supposed to to

 function rowfcn = make_nextRow(array, start_row)
  %
  % rowfcn = make_nextRow(array, start_row)
  % 
  % Returns a function handle, rowfcn.  When the function handle
  % is firet called, it will return the row defined by start_row.
  % Every call afterwards will return the next row below.
  %
  % If there are no more rows to return, an empty array, [], is returned.
  %
  % Inputs:
  %   array - A numerical MxN array 
  %   start_row - An index (integer) that indicates 
  %               which row to start returning values from
  %
  % Outputs:
  %   rowfcn - A handle to nextRow, which when alle
  %
M = start_row;
rowfcn = @nextRow; %Return a handle to the NESTED function, nextRow()
end
      function row = nextRow()
          % Check if M is within size(array) and if it is greater than 0
          if M <= array(size) && M > 0
              row = array(M,:);  % Get the M'th row from array and assign to row
              M= M+ 1;             % Increment M
          else
              row = [];
          end
      end

*this is the test case I used: *

scores = [20,90;13,56;3,67;10,78;2,54]

next_score = make_nextRow(scores,1)

next_score()

next_score = make_nextRow(scores,4)

next_score()

these are the answers i'm supposed to get for my test case:

>> scores = [20,90;13,56;3,67; 10,78;2,54]

>>scores=

20 90 13 56 3 67 10 78 2 54

>> next_score = make_nextRow(scores,1)

next_score =

@make_nextRow/nextRow

>> next_score()

ans = 20 90

>> next_score()

ans = 13 56

>> next_score = make_nextRow(e7_scores,4)

 next_score =
        @make_nextRow/nextRow

>> next_score()

ans = 10 78

>> next_score()

ans = 2 54

>> next_score()

ans = []

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Answer 1

per isakson 2012-10-14

2
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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/50776-nested-loop-not-working#answer_61940

编辑：per isakson 2012-10-14

在 MATLAB Online 中打开

Problems with your code:

nextRow() is not properly defined as a nested function but rather as a subfunction. As a consequence the input arguments, array and start_row, are "lost".
IMO: "M" is not an appropriate name for a row number.
"array(size)" should be "size( array, 1 )"
"nested loop" in the title is misleading

Your comments and programming style is good

I've modified the code (see below) and run

    scores = [20,90;13,56;3,67;10,78;2,54];
    next_score = make_nextRow( scores, 1 )
    next_score()
    next_score()

which returns

    next_score = 
        @make_nextRow/nextRow
    ans =
        20    90
    ans =
        13    56
    >>

where

    function rowfcn = make_nextRow( array, start_row )
    M = start_row;
    rowfcn = @nextRow; %Return a handle to the NESTED function, nextRow()
        function row = nextRow()
            if M <= size( array, 1 ) && M > 0
                row = array( M, : ); 
                M= M+ 1;             
            else
                row = [];
            end
        end
    end

.

I don't know if that is the expected result. I let you check that.

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Ping 2012-10-14

but the first part is just the test case so I can't edit that. I edited the question to make it clearer

per isakson 2012-10-14

编辑：per isakson 2012-10-14

I don't understand!

I have:

fixed a few problems in your function, make_nextRow
deleted blank lines and comments to keep the answer compact
demonstrated that it returns numbers, which you have confirmed are indeed those expected.

What more do you expect?

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