Why do I receive empty outputs in cell arrays after an if statement?

Question

gsourop 2018-10-25

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/426052-why-do-i-receive-empty-outputs-in-cell-arrays-after-an-if-statement

评论： Adam Danz 2018-10-25

采纳的回答： Dennis

在 MATLAB Online 中打开

Hi everyone,

I am applying an if statement in doubles and allocate outputs in cell arrays, such as

stars{1}='*'; stars{2}='**'; stars{3}='***-';
crvalue{1} = 1.282; crvalue{2} = 1.645; crvalue{3} = 2.326;
for i = 1 : 8
    C = randn(17,2);
        for j = 1 :size(C,1)
        if C(j,2) > crvalue{1}
            results{j,i} = sprintf('%.2f%s', C(j,1), stars{1});
            if C(j,2) > crvalue{2}
                results{j,i} = sprintf('%.2f%s', C(j,1), stars{2});
                if C(j,2) > crvalue{3}
                    results{j,i} = sprintf('%.2f%s', C(j,1), stars{3});
                    if C(j,2) < crvalue{1}
                        results{j,i} = C(j,2);
                    end
                end
            end
        end
    end
end

I am only doing one-sided hypothesis testing and want to find an easier way to get my results. However, the cell array 'results' delivers empty cells.

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Answer 1

Dennis 2018-10-25

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/426052-why-do-i-receive-empty-outputs-in-cell-arrays-after-an-if-statement#answer_343368

编辑：Dennis 2018-10-25

在 MATLAB Online 中打开

You nested your if statements, hence the last statement

if C(j,2) < crvalue{1}

will only be executed if the previous statements are true.

stars{1}='*'; stars{2}='**'; stars{3}='***-';
  crvalue{1} = 1.282; crvalue{2} = 1.645; crvalue{3} = 2.326;
  for i = 1 : 8
      C = randn(17,2);
          for j = 1 :size(C,1)
          if C(j,2) > crvalue{3}
              results{j,i} = sprintf('%.2f%s', C(j,1), stars{3});
          elseif C(j,2) > crvalue{2}
                  results{j,i} = sprintf('%.2f%s', C(j,1), stars{2});
          elseif C(j,2) > crvalue{1}
                      results{j,i} = sprintf('%.2f%s', C(j,1), stars{1});
          elseif C(j,2) < crvalue{1}
                          results{j,i} = C(j,2);
          end
          end
  end

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Stephen23 2018-10-25

+1 well spotted

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Answer 2

Adam Danz 2018-10-25

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/426052-why-do-i-receive-empty-outputs-in-cell-arrays-after-an-if-statement#answer_343370

编辑：Adam Danz 2018-10-25

在 MATLAB Online 中打开

This version is a lot cleaner and fixes some other issues in your code such as allocating the results cell array.

stars{1}='*'; stars{2}='**'; stars{3}='***-';
crvalue = [1.282, 1.645, 2.326];
results = cell(17, 8); 
for i = 1 : 8
    C = randn(17,2);
    for j = 1 :size(C,1)
        g = max(find( C(j,2) > crvalue, length(crvalue)));
        if isempty(g)
            results{j,i} = C(j,2);
        else
            results{j,i} = sprintf('%.2f%s', C(j,1), stars{g});
        end
    end
end
results =
  17×8 cell array
    {[-0.17809]}    {[ 0.21487]}    {[  0.1679]}    {'2.16*'    }    {[-0.22357]}    {[  -1.2048]}    {[-0.076898]}    {[ 0.81204]}
    {[ -1.2298]}    {[ 0.79815]}    {'0.81*'   }    {[ -0.78924]}    {[ -1.8436]}    {[  -1.2214]}    {[ -0.79468]}    {[-0.82839]}
    {[ 0.23592]}    {[ 0.66115]}    {[ 0.13897]}    {[  0.28164]}    {[  1.2646]}    {[ -0.93917]}    {[ -0.86142]}    {[-0.96019]}
    {[ -1.5158]}    {[ 0.80677]}    {'-0.19**' }    {[  0.91823]}    {[0.052461]}    {[  0.12853]}    {[  0.15585]}    {[-0.44851]}
    {[ 0.14905]}    {[ -1.3359]}    {'0.09*'   }    {[-0.072479]}    {[ 0.39338]}    {[  0.22861]}    {[  0.24215]}    {[ 0.79749]}
    {'-0.05**' }    {[  0.1088]}    {[ 0.51407]}    {[  -0.4045]}    {[-0.68554]}    {[  0.67834]}    {[ -0.23146]}    {[-0.23779]}
    {[ -2.0189]}    {[ -1.6722]}    {[  1.1261]}    {[ -0.70628]}    {[ -1.4358]}    {[ -0.56188]}    {[  -1.0168]}    {[-0.26382]}
    {[-0.49984]}    {[ 0.67732]}    {[-0.61416]}    {[ -0.37119]}    {[ 0.22429]}    {[ 0.022608]}    {[  -1.1964]}    {[ -0.1657]}
    {[   1.086]}    {[-0.12485]}    {[-0.58216]}    {[  0.22281]}    {[ 0.49732]}    {[ -0.42034]}    {[  -1.8448]}    {[ 0.74226]}
    {[ 0.91469]}    {'-0.54**' }    {[ -1.6322]}    {[  0.67979]}    {[-0.51625]}    {[  -1.0327]}    {[ -0.02224]}    {[ 0.43704]}
    {[-0.31121]}    {[ 0.58413]}    {[-0.25497]}    {[  -1.2525]}    {[-0.59535]}    {[   1.0832]}    {[  -0.7387]}    {[-0.28457]}
    {[  1.2332]}    {[ 0.16294]}    {'-0.17**' }    {[  0.65908]}    {[  1.0631]}    {[-0.013716]}    {[  0.39654]}    {[  0.4468]}
    {[-0.75311]}    {'-2.48*'  }    {[-0.59098]}    {[   1.0899]}    {[ 0.22924]}    {[   0.8879]}    {[   1.2352]}    {[  1.1911]}
    {[-0.35791]}    {[ 0.57181]}    {[ 0.11582]}    {[0.0011519]}    {[  0.1029]}    {[  0.35997]}    {[ -0.52432]}    {[ 0.20621]}
    {[-0.78979]}    {[ 0.26162]}    {[ 0.72697]}    {[ -0.23341]}    {[ 0.35146]}    {[ -0.21522]}    {[  -1.0894]}    {[ 0.76702]}
    {[ -1.5112]}    {[ -1.7766]}    {[-0.74442]}    {[  0.71567]}    {'1.25***-'}    {[  0.41003]}    {[  0.58509]}    {[ -0.8177]}
    {[ -1.7082]}    {[  1.2142]}    {[-0.45693]}    {[  -0.1592]}    {'0.55**'  }    {[ 0.088993]}    {'2.14**'   }    {[  0.7668]}

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gsourop 2018-10-25

在 MATLAB Online 中打开

Hi there,

Thank for your time to answer my question. When I run the code I get an error 'Undefined operator '>' for input arguments of type 'cell'

The code I run is

    stars{1}='*'; stars{2}='**'; stars{3}='***-';
    crvalue{1} = 1.282; crvalue{2} = 1.645; crvalue{3} = 2.326;
    for i = 1 : 8
        C = randn(17,2);
        for j = 1 :size(C,1)
            g = max(find( C(j,2) > crvalue, length(crvalue)));
            if isempty(g)
                results{j,i} = C(j,2);
            else
                results{j,i} = sprintf('%.2f%s', C(j,1), stars{g});
            end
        end
    end
    results