Conditional if statement solution

Question

Tino 2019-8-15

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/476259-conditional-if-statement-solution

回答： Rik 2019-8-15

采纳的回答： Rik

I will greatly appreciate it if any one assist me in solving this problem in Matlab code

For instance I have a list of values = 3 4 6 3 4 5 10 7 4 5 3 4

The code contains two if statement

if values > 9

in this case it is in position 7 : display the positions in values that meet condition ( if value > 9) in the example above it is the 7th position (10)

then calculate the 5 numbers before and after including position 7th (10) itself an example

average = (4 + 5 + 10 + 7 + 4 )/5 = 6

if (average > 9)

true changes showing ( 7th position = 10 )

else

false changes (7th position = 10 )

end if statement

The answer is false change detection

I will like to be assisted with the code as I want to apply these to large data

Thanks in advance

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Geoff Hayes 2019-8-15

So you will want to find all elements that are greater than nine and then apply the logic to each one presumably storing the result of each in an array.

Tino 2019-8-15

Yes Geoff with a discription if they are true changes or false changes

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Answer 1

Rik 2019-8-15

2
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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/476259-conditional-if-statement-solution#answer_387710

In Matlab calculating parameters for the entire array at once is almost always faster than a loop. My code below uses the find function (as Geoff hinted at), and it uses a convolution to find the moving average for each position. You should check if this matches your requirements for the edge cases. If you want to display the results in a different way, you should be able to add code that suits your need.

values =[3 4 6 3 4 5 10 7 4 5 3 4];
window=ones(1,5)/5;
avg=conv(values,window,'same');
true_changes=find( values>9 & avg>9 );
false_changes=find( values>9 & avg<=9 );