Potting graphs with if else and for

Question

Gayathri Thilakrathne 2020-11-5

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/636990-potting-graphs-with-if-else-and-for

编辑： Walter Roberson 2021-1-7

Here i wanted to plot a graph wit these conditions. but it does not plot a graph. figure remains empty without a graph. how can i fix this

t = -4:0.1:4;
    for k1 =1:length(t)
        if (t(k1)>-4) && (t(k1)<-2)
             x(k1) = (t(k1).^2) - (2.*t(k1))+3;
        elseif (t(k1)>-2) && (t(k1)<2)
             x(k1) = 4*cos(t(k1)*(2*pi*t(k1) - pi./8)) + 3*sin(2*pi*t(k1));
        elseif (t(k1)>2) && (t(k1)<4)
             x(k1) = sin(t(k1))./t(k1);
    end
end
plot (t,x)

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Sindar 2020-11-5

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/636990-potting-graphs-with-if-else-and-for#answer_534810

If it throws an error, please include that information.

If that error is what I'm seeing:

Error using plot. Vectors must be the same length.

then the issue is that you're conditions don't include an x-value when t=4 (or -2,2, but these will be filled in with zeros). You can use <=, >=, or you don't want those points plotted, insert NaNs:

t = -4:0.1:4;
for k1 =1:length(t)
    if (t(k1)>-4) && (t(k1)<-2)
        x(k1) = (t(k1).^2) - (2.*t(k1))+3;
    elseif (t(k1)>-2) && (t(k1)<2)
        x(k1) = 4*cos(t(k1)*(2*pi*t(k1) - pi./8)) + 3*sin(2*pi*t(k1));
    elseif (t(k1)>2) && (t(k1)<4)
        x(k1) = sin(t(k1))./t(k1);
    else
        x(k1) = nan;
    end
end
plot(t,x)