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How to create a numerical variable from a string stored in a cell array ?

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azr124
azr124 on 15 Mar 2017
Commented: azr124 on 15 Mar 2017
I have a cell array that looks as follows:
countrycode = {'ALB';'ALB';'ALB';'ARG';'ARG';'BRA';'BRA';'BRA';'BRA'}
This is a short example, the list has about 50 countries, each with a different number of entries.
1. How can I create a numerical variable that assigns the value 1 to all 'ALB' entries, 2 to all 'ARG' entries, 3 to all 'BRA' entries and so on? 2. Is there a command akin to 'foreach' that would allow me to loop over all possible country codes? for instance, to extract data in a numerical variable associated with the variable countrycode?

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Accepted Answer

Alexandra Harkai
Alexandra Harkai on 15 Mar 2017
To get the numeric values:
country_idx = findgroups(countrycode);
For the second part, it really depends on what is it exactly you want to do. splitapply till likely be a helpful, for example, to count the number of entries within each country:
splitapply(@numel, countrycode, country_idx)

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azr124
azr124 on 15 Mar 2017
Thanks Alexandra! Once I have the numerical values I can use these for looping.

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More Answers (1)

Rik
Rik on 15 Mar 2017
You can use unique to generate the list of codes, followed by ismember to find out the locations, so the result is a vector.
countrycode = {'ALB';'ALB';'ALB';'ARG';'ARG';'BRA';'BRA';'BRA';'BRA'};
list=unique(countrycode);
[~,Locb] = ismember(countrycode,list);
To my knowledge there is no foreach command in Matlab, but you can use a for-loop to loop over all the possible values. I suspect what you want may also be achieved without a loop, but you'dd have to tell us more about what exactly you want to do.

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