# counting the number of rows that satisfy a certain criteria

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## counting the number of rows that satisfy a certain criteria

 I have 4 columns, and about 300K plus rows with 0s and 1s. I'm trying to count how many rows satisfy a certain criteria... for instance, how many rows are there that have the first column == 1 as well as the second column == 1. I've tried using rowSums and colSums but it keeps giving me this type of error: Error in rowSums(X[1] == 1 & X[2] == 1) :   'x' must be an array of at least two dimensions Thanks in advance! ______________________________________________ [hidden email] mailing list https://stat.ethz.ch/mailman/listinfo/r-helpPLEASE do read the posting guide http://www.R-project.org/posting-guide.htmland provide commented, minimal, self-contained, reproducible code.
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## Re: counting the number of rows that satisfy a certain criteria

 Hi Kate, You could try sum(X[, 1] == 1 &  X[, 2] == 1) where X is your data set. HTH, Jorge.- On Sun, Jun 22, 2014 at 12:57 AM, Kate Ignatius <[hidden email]> wrote: > I have 4 columns, and about 300K plus rows with 0s and 1s. > > I'm trying to count how many rows satisfy a certain criteria... for > instance, how many rows are there that have the first column == 1 as > well as the second column == 1. > > I've tried using rowSums and colSums but it keeps giving me this type of > error: > > Error in rowSums(X[1] == 1 & X[2] == 1) : >   'x' must be an array of at least two dimensions > > Thanks in advance! > > ______________________________________________ > [hidden email] mailing list > https://stat.ethz.ch/mailman/listinfo/r-help> PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html> and provide commented, minimal, self-contained, reproducible code. >         [[alternative HTML version deleted]] ______________________________________________ [hidden email] mailing list https://stat.ethz.ch/mailman/listinfo/r-helpPLEASE do read the posting guide http://www.R-project.org/posting-guide.htmland provide commented, minimal, self-contained, reproducible code.