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Combine for loop output??

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Jonathan Good
Jonathan Good on 4 May 2018
Edited: Wick on 4 May 2018
Hi I'm writing some code for my homework that will allow the user to choose a number of lines they want to buy in a lottery. My code is generating the numbers in the desired range, it is outputting the numbers from a for loop for the specified number of times, ultimately i want the combined output to go into a table to display all of the results. The purpose of the exercise isn't to be sleek its to use a variety of functions in one piece of code. Here's what i have so far:
% I am producing a code that will allow the
% user to choose a desired number of lines required for a euromillions
% lottery draw (Max 7 per slip)
User select number of lines they would like
number_of_lines = menu('Hello there welcome to the lottery draw please select a number of lines you wish to purchase? Remember its £2.50 a line and 7 lines maximum per ticket', '1','2','3','4','5','6','7');
% function to generate number of lines selected
% row vectors containing limits for numbers
main_draw_numbers = (1:50)
lucky_stars = (1:12)
% preallocate the output array
main_draw = zeros(number_of_lines,5);
% preallocate the output array
stars_draw = zeros(number_of_lines,2);
for draw=1:number_of_lines
% increment counter
main_draw = sort(datasample(main_draw_numbers,5,'Replace',false));
stars_draw = sort(datasample(lucky_stars,2,'Replace',false));
full_draw = [main_draw stars_draw];
T = array2table(full_draw,...
'VariableNames',{'Ball_1','Ball_2','Ball_3','Ball_4','Ball_5','Lucky_star_1','Lucky_star_2'})
end

  3 Comments

Jonathan Good
Jonathan Good on 4 May 2018
managed to use the table2array command in the loop just need to get it to include the lucky stars and then combine the numbers from each generated loop so tricky for me
Wick
Wick on 4 May 2018
You're only adding one line to the table - not concatenating them together for each draw. I've edited my solution. See if you like it better.
Wick
Wick on 4 May 2018
I see you edited the code so it combines the full and stars draws in the FOR loop. But if you don't cat the loops together you're still going to get a single line in your table.
Something like
full_draw = [];
for ...
full_draw = [full_draw; main_draw stars_draw];
end

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Accepted Answer

Wick
Wick on 4 May 2018
Edited: Wick on 4 May 2018
If you're not trying to be pretty or efficient you can do the following:
for draw=1:number_of_lines
% increment counter
main_draw = datasample(main_draw_numbers,5,'Replace',false);
stars_draw = datasample(lucky_stars,2,'Replace',false);
if draw == 1
T = array2table([main_draw stars_draw],...
'VariableNames',{'ball1','ball2','ball3','ball4','ball5','Lucky1','Lucky2'});
else
T = [T; array2table([main_draw stars_draw],...
'VariableNames',{'ball1','ball2','ball3','ball4','ball5','Lucky1','Lucky2'})];
end
end
"Proper" MATLAB would be to pre-allocate the memory for table T. But this works for a small 'for' loop like this.
Rather than initialize, I jsut made an IF statement decide to start the table or cat to it.

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