Storing values calculated in a 'for' loop in a matrix / vector
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I would very much appreciate some help storing values in a matrix. I am trying to do a growth curve (See: http://kellymom.com/images/growth/growthcharts.gif). For that reason I have to do quantile equations for a set of data (age and height). Currently, I've made a 'for' loop, which does calculate the value as intended, however it only stores the last result. How do I make it store the data as a matrix like:
Quantile 25 %
Age Height
- 6 123
- 7 129
- 8 135
and so forth.
Thank you very much!
Note: male.data consists of two columns. First column is age and second is height of two thousand male participants. The file: age.height.mat is my data.
[EDITED, Jan, contents of the M-file from dropbox:]
%%Assignment 1 - Growth curves for men and women
clear all ;
clc ;
load age.height.mat
% Sorting the data to be plotted
male.data = sortrows(male.data) ;
plot(male.data(:,1),male.data(:,2),'r+')
male.growth = zeros(1, 73);
t = zeros(1, 73);
for k = 6:78
male.growth(k-5) = male.data(male.data(:,1) == k, 2);
t(k-5) = quantile(male.growth(k-5), 0.5);
end
% Note that t sometimes returns 'not a number', when a specific age is not
% present. That won't be a problem in my final script, as I am not allowed
% to publish all my data for copyright reasons.
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Jan
2013년 3월 13일
편집: Jan
2013년 3월 13일
Please do not start your code with the cruel killer. There is no benefit in removing all loaded functions from the memory by clear all. If you have a good reason to clear all variables, use clear variables or even better use a function, because it has its own workspace.
For storing the results in a vector:
male.growth = zeros(1, 73); % Pre-allocate!!! Optional but recommended
t = zeros(1, 73);
for k = 6:78 % Avoid using "i" as a variable
male.growth(k-5) = male.data(male.data(:,1) == k, 2); % Without FIND
t(k-5) = quantile(male.growth(k-5), 0.5);
end
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Jan
2013년 3월 18일
@Tobias: While for:
male.growth = male.data(male.data(:,1) == k, 2);
the dimensions on the left side are adjusted automatically, as for:
male.growth(100) == 8;
the missing elements are set to implicitely, a vector cannot assigned to a scalar:
a(1) = 1:10; % ERROR
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