Question

我写了一个函数来按照其中一个字段对玩家对象进行排序：

function [ sortedPlayers ] = sortPlayers(players)
%sorts player objects by rating
    playersFields = fieldnames(players);
    playersCell = struct2cell(players);
    sz = size(playersCell);

    playersCell = reshape(playersCell, sz(1), []);
    playersCell = playersCell';
    playersCell = sortrows(playersCell, -3);

    playersCell = reshape(playersCell', sz);
    sortedPlayers = cell2struct(playersCell, playersFields, 1);
end

运行时，我收到此错误：

    Undefined function 'fieldnames' for input arguments of type 'double'.

Error in sortPlayers (line 4)
    playersFields = fieldnames(players);

Error in getTeamPlayers (line 16)
    teamPlayers = sortPlayers(teamPlayers);

Error in masterSimulate (line 13)
    firstTeam = getTeamPlayers(team_dict, firstTeamName);

Error in mainMenu (line 25)
                masterSimulate(team_dict);

Error in main (line 18)
mainMenu(team_dict, allPlayers);

我用谷歌搜索过，大多数时候这种类型的错误是由一个函数命名的，与其所在的文件不同。但是，“fieldnames”是一个内置函数。我跑：

which fieldnames -all

然后回来：

built-in (/Applications/MATLAB_R2011b.app/toolbox/matlab/datatypes/@struct/fieldnames)             % struct method
built-in (/Applications/MATLAB_R2011b.app/toolbox/matlab/datatypes/@opaque/fieldnames)             % opaque method
fieldnames is a built-in method                                                                    % meta.PackageList method
fieldnames is a built-in method
...

知道这里发生了什么吗？我不认为我在sortPlayers函数中改变了任何内容，所以我很遗憾：为什么它不再正常工作。

谢谢！

Answer 1

看起来像你调用它时传递给函数的参数不是类struct，用户定义的类或Java类，而是其他东西（double可能？）。< / p>

要测试参数的类，只需在函数的开头添加：

 fprintf(1, '"players" has the type "%s".\n', class(players));

然后再次调用您的函数（或运行为您调用它的应用程序）。

“double”类型的输入参数的未定义函数“fieldnames”

1 个答案: