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I am dealing with a fourth order polynomial. I get all of the desired out put however above a certain range I also get these - {}. From my understanding this means that there is no solution. I am trying to plot the final output however {} runes any chance of that. How could I remove the 'no solution'?

I have tried Select and Reduce.

Ddd = (a1) Dd^4 - (a2) Dd + (a2);
Table[NSolve[Ddd == 0, Dd, Reals], {t, t3}];

My output looks like this:

{{1.*10^-7, 0.000312683}, {1.0056*10^-7, 5.29149*10^-7}, {1.01653*10^-7, 3.59975*10^-7}, {1.0323*10^-7,  2.83353*10^-7}, {1.05406*10^-7, 2.36121*10^-7}, {1.08473*10^-7, 2.02102*10^-7}, {1.13219*10^-7, 1.74367*10^-7}, {1.23859*10^-7,   1.45755*10^-7}, {}, {}, {}, {}, {}, {}, {}, {}, {}, {}, {}, {}, {}}

I would just like to retain all the numbers an non of the rest.

Cheers for any ideas.

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1 Answer 1

up vote 1 down vote accepted

A couple of ways:

sols = {{1.*10^-7, 0.000312683}, {1.0056*10^-7, 
    5.29149*10^-7}, {1.01653*10^-7, 3.59975*10^-7}, {1.0323*10^-7, 
    2.83353*10^-7}, {1.05406*10^-7, 2.36121*10^-7}, {1.08473*10^-7, 
    2.02102*10^-7}, {1.13219*10^-7, 1.74367*10^-7}, {1.23859*10^-7, 
    1.45755*10^-7}, {}, {}, {}, {}, {}, {}, {}, {}, {}, {}, {}, {}, \
{}};


DeleteCases[sols, {}]
sols /. {} -> Sequence[]

Side remark:

If your code is

sols = Table[NSolve[Ddd == 0, Dd, Reals], {t, t3}];

then the output should have the form

((sol11, sol12,...), {sol21,...}, ..., {}, {}, ...}

If so, you can get rid of the {} with

Flatten[sols, 1]
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Thank you very much Michael, that worked perfectly. I spent a really long time trying to find a way around it, I did not realize mathematica had this function...so much to learn. –  ValentinU Nov 18 at 15:22
    
@ValentinU You're welcome. –  Michael E2 Nov 18 at 17:43

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