[R] maximum of identical elements in a vector
Hi, the problem I have is seemingly very simple, but not simple enough for me to figure out. I just want to find the most (or least) frequent element in the vector. a=c(Alice,Alice,Alice,Alice,Bob,Bob) unique(a) length(which(a==Alice)) unique(a) shows me that the elements in my vector are Alice and Bob. The latter expression gives 4 as the frequency of Alice in vector a. To find the maximum frequency of the unique elements, however, it assumes that I know that Alice is the most (or least) frequent element. Therefore, how can find that Alice is the most frequent element in this vector? I assume there is an easier way than computationally intensive loops (for long vectors). Cheers, Daniel - cuncta stricte discussurus __ R-help@r-project.org 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.
Re: [R] maximum of identical elements in a vector
On 3/30/2008 5:35 PM, Daniel Malter wrote: Hi, the problem I have is seemingly very simple, but not simple enough for me to figure out. I just want to find the most (or least) frequent element in the vector. a=c(Alice,Alice,Alice,Alice,Bob,Bob) unique(a) length(which(a==Alice)) unique(a) shows me that the elements in my vector are Alice and Bob. The latter expression gives 4 as the frequency of Alice in vector a. To find the maximum frequency of the unique elements, however, it assumes that I know that Alice is the most (or least) frequent element. Therefore, how can find that Alice is the most frequent element in this vector? I assume there is an easier way than computationally intensive loops (for long vectors). names(which.max(table(a))) [1] Alice Cheers, Daniel - cuncta stricte discussurus __ R-help@r-project.org 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. -- Chuck Cleland, Ph.D. NDRI, Inc. (www.ndri.org) 71 West 23rd Street, 8th floor New York, NY 10010 tel: (212) 845-4495 (Tu, Th) tel: (732) 512-0171 (M, W, F) fax: (917) 438-0894 __ R-help@r-project.org 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.
Re: [R] maximum of identical elements in a vector
On Sun, 2008-03-30 at 17:35 -0400, Daniel Malter wrote: Hi, the problem I have is seemingly very simple, but not simple enough for me to figure out. I just want to find the most (or least) frequent element in the vector. a=c(Alice,Alice,Alice,Alice,Bob,Bob) unique(a) length(which(a==Alice)) a - c(Alice,Alice,Alice,Alice,Bob,Bob) tab - table(a) tab a Alice Bob 4 2 which.max(tab) Alice 1 tab[which.max(tab)] Alice 4 HTH G unique(a) shows me that the elements in my vector are Alice and Bob. The latter expression gives 4 as the frequency of Alice in vector a. To find the maximum frequency of the unique elements, however, it assumes that I know that Alice is the most (or least) frequent element. Therefore, how can find that Alice is the most frequent element in this vector? I assume there is an easier way than computationally intensive loops (for long vectors). Cheers, Daniel - cuncta stricte discussurus __ R-help@r-project.org 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. -- %~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~% Dr. Gavin Simpson [t] +44 (0)20 7679 0522 ECRC, UCL Geography, [f] +44 (0)20 7679 0565 Pearson Building, [e] gavin.simpsonATNOSPAMucl.ac.uk Gower Street, London [w] http://www.ucl.ac.uk/~ucfagls/ UK. WC1E 6BT. [w] http://www.freshwaters.org.uk %~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~% __ R-help@r-project.org 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.
Re: [R] maximum of identical elements in a vector
Thanks to all who responded so quickly. - cuncta stricte discussurus - -Ursprüngliche Nachricht- Von: Chuck Cleland [mailto:[EMAIL PROTECTED] Gesendet: Sunday, March 30, 2008 5:45 PM An: Daniel Malter Cc: [EMAIL PROTECTED] Betreff: Re: [R] maximum of identical elements in a vector On 3/30/2008 5:35 PM, Daniel Malter wrote: Hi, the problem I have is seemingly very simple, but not simple enough for me to figure out. I just want to find the most (or least) frequent element in the vector. a=c(Alice,Alice,Alice,Alice,Bob,Bob) unique(a) length(which(a==Alice)) unique(a) shows me that the elements in my vector are Alice and Bob. The latter expression gives 4 as the frequency of Alice in vector a. To find the maximum frequency of the unique elements, however, it assumes that I know that Alice is the most (or least) frequent element. Therefore, how can find that Alice is the most frequent element in this vector? I assume there is an easier way than computationally intensive loops (for long vectors). names(which.max(table(a))) [1] Alice Cheers, Daniel - cuncta stricte discussurus __ R-help@r-project.org 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. -- Chuck Cleland, Ph.D. NDRI, Inc. (www.ndri.org) 71 West 23rd Street, 8th floor New York, NY 10010 tel: (212) 845-4495 (Tu, Th) tel: (732) 512-0171 (M, W, F) fax: (917) 438-0894 __ R-help@r-project.org 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.
