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POCreating a dummy variable according to data in a matrix in R
 

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  1. POCreating a dummy variable according to data in a matrix in R
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    <p>I have a dataframe with 1000 observations belonging to n different countries. Each country has more than 1 observation and the number of observations of each country differ. I need to create a column with numbers going from (1 to n-1), with each number corresponding to a different country. That is, I am creating a dummy variable and I don't care which country has which number. I just need to create such dummies. My data are something like this</p> <pre><code> Region x 1 be1 71615 4 be211 54288 5 be112 51158 6 it213 69856 8 it221 71412 9 uk222 79537 10 de101 94827 11 de10a 98273 12 dea10 92827 .. .. .. </code></pre> <p>Each country has its own "code" in the column Region, for instance beXXXX correpsonds to Belgium, ukXXX to the United Kingdom and so on. Hence I suppose I could exploit the initial <strong>2</strong> letters in the column Region to create my dummies. I know from <a href="https://stackoverflow.com/questions/7562233/how-do-i-select-variables-in-an-r-dataframe-whose-names-contain-a-particular-str">here</a> that the command <code>grep()</code> could do the job, but I need to have a script which automatically switches from 1 to n-1 whenever the initial letters of the Region change.</p> <p>The expected output should be like this</p> <pre><code> Region x Dummy 1 be1 71615 1 4 be211 54288 1 5 be112 51158 1 6 it213 69856 2 8 it221 71412 2 9 uk222 79537 3 10 de101 94827 4 11 de10a 98273 4 12 dea10 92827 4 .. .. .. .. </code></pre> <p>and in this case 1 corresponds to "be" (Belgium), 2 to "it" (Italy) and so on for the ´n´countries in my sample.</p>
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    1. USBob
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    1. COPlease post expected output from your example input...
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      1. USFredrik Pihl
    2. COYou are right. I posted the expected output. I want to stress that the dataframe is ordered by region (and hence by country), that is I have first all the beXXX observations, then the itXXXX and so on. Maybe this can be exploited to make things simpler.
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      1. USBob
 

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