How do I make a script that outputs all numbers containing a certain set of digits?
1 view (last 30 days)
Show older comments
Say I want to make a vector containing all numbers with the digits [2,4,5,7,9], so 25497, 95742, etc. How can I make a script that puts all numbers in this vector?
I've tried the following:
%
vec = zeros (1,factorial(5));
i = 0
while i < factorial(5)
num = 0;
ii = 0;
iii = [2,4,5,7,9];
while ii < 5; % This while loop creates a number
randnum = randi(5);
eval = iii(randnum);
if eval > 0
num = num + eval*10^(ii);
iii(randnum) = 0;
ii = ii + 1;
end
end
if not(ismember(num,vec(:))) %This if-statement checks if the number had already been created earlier
i = i + 1;
vec(i) = num; %If not, it is added to the vector
end
end
but it is impressively inelegant and simply takes too long for larger amounts of numbers.
0 Comments
Accepted Answer
Kai Domhardt
on 9 Feb 2018
digits = [2,4,5,7,9];
sum(perms(digits).*10.^[size(digits,2)-1:-1:0],2);
---
perms(digits)
creates all permutations of digits
10.^[size(digits,2)-1:-1:0]
creates a vector with the relevant orders of magnitude:
ans =
10000 1000 100 10 1
which you can use to give your digits the right positional value:
perms(digits).*10.^[size(digits,2)-1:-1:0]
Now you only need to sum it up row wise:
sum( perms(digits).*10.^[size(digits,2)-1:-1:0] ,2)
0 Comments
More Answers (0)
See Also
Categories
Find more on Whos in Help Center and File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!