使用saveas进行绘图时出错

Question

当我尝试在MATLAB中保存绘图时，我收到此错误：

??? Operands to the || and && operators must be convertible to logical scalar values.

Error in ==> saveas at 64
    while ~isempty(h) &&  ~isfigure(h)

Error in ==> LongDistanceHistogram at 155
     saveas(p, ['hotspot-histograms/ddi' num2str(ddi_ctr) '.png']);

我的情节代码如下所示，错误发生时会显示正确显示情节的窗口：

 clf;
 nums = [wrongratio truthratio];
 [counts, centers] = hist(nums,20);
 p = bar(centers, counts);
 hold on;
 title(['DDI ' num2str(ddi_ctr)]);
 xlabel('% increase in score from long-distance information');
 ylabel('Count');
 legend('Random sampling', 'Fixed M_i states', 'Location', 'Northwest');
 saveas(p, ['hotspot-histograms/ddi' num2str(ddi_ctr) '.png']);     

有谁知道什么是错的？当我在做线图时，这工作正常，但我尝试改为条形似乎打破了它。