loop not recording array
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I am trying to get the IF statement to record which numbers when the "Differences" function is higher than the avgdiff
clc; clear;
rainfall = readmatrix('RainFall.txt');
% Reading the text file and turning it into a double^
dates = rainfall(:,1);
number = rainfall(:,2);
raininches = rainfall(:,3);
% Specifying the data we want from the text file^
plot(dates,raininches,'-o')
xlabel('years')
ylabel('Inches of rain')
% Plots the information above and labels the axis's
floods = [];
count = 1;
hold on
differences = zeros(length(raininches),1);
% Creates and array with a column to store the values of differences^
for n = 2:length(raininches)
% For loop starting at 2 so it can properly calculate the differences^
differences = raininches(n) - raininches(n - 1);
% Takes each years rain in inches and subtracts them from the previous
% year to find the difference between each years rain fall^
avgdiff = mean(differences);
% finds the Average difference accross all recorded years^
if differences > avgdiff
% Loops to check if those 2 years difference is higher than the average
% difference over the recorded years
floods(count) = [n,1];
% If it is higher, it records the difference in an Array here^
end
count = count + 1;
end
yline(avgdiff,'r')
% Plots the Average Difference of all the years combined^
legend('Rain each year','Average Difference over time')
% Creates a legend for both plots^
hold off
x = dates(floods(count),1);
fprintf('Each of these years have a higher probability of flash floods: \n', x)
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Answers (2)
Walter Roberson
on 1 Dec 2023
for n = 2:length(raininches)
n will be a scalar inside the loop.
differences = raininches(n) - raininches(n - 1);
scalar indexing minus scalar indexing: the result will be a scalar.
avgdiff = mean(differences);
mean() of a scalar will be the scalar itself.
if differences > avgdiff
Because the mean of a scalar is the scalar itself, it is not possible for the scalar in differences to be greater than the (same) scalar in avgdiff
4 Comments
Walter Roberson
on 1 Dec 2023
You can use a loop to calculate the difference at a "current" position and record that difference in an array. You can add the current difference to a total difference that you are accumulating. After the loop you can divide the total difference by an appropriate number to determine the average difference.
After that you can loop over the already-recorded current differences and compare each of them to the calculated average difference, and do whatever is appropriate
madhan ravi
on 1 Dec 2023
Edited: madhan ravi
on 1 Dec 2023
Note: Handcoded from memory. Loops are unnecessary in this case.
differences = diff(raininches);
avgdiff = mean(differences);
x = dates(differences > avgdiff);
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