# list contingency tables

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## list contingency tables

 Hi all,   I am trying to list all the 4 by 2 tables with some fixed margins.   For example, consider 4 by 2 tables with row margins 1,2,2,1 and column margins 3,3. I was able to do it using the code below. However, as seen below, I had to first count the total number of tables with the specific row margins and column margins in order to create space to store the tables. Is there a way to skip the step of counting the number of tables?   Also, wanted to avoid for loops as much as possible since it can be extremely slow and inefficient.    Thanks so much in advance for you insight and help.        Hanna > library(gtools) > A <- permutations(n=4,r=2,v=0:3, repeats.allowed=TRUE) > B <- apply(A, 1, sum) > rmg <- c(1,2,2,1) > cmg <- c(3,3) > m1 <- t(A[which(B==1),]) > m2 <- t(A[which(B==2),]) > m3 <- t(A[which(B==2),]) > > ##count number of tables with row margins 1,2,2,1 and column margins 3,3. > num <- 0 > for (i in 1:ncol(m1)){ +     for (j in 1:ncol(m2)){ +         for (k in 1:ncol(m3)){ +             M <- t(cbind(m1[,i], m2[,j], m3[,k])) +             M1 <- rbind(M, cmg-apply(M,2,sum)) +             num <- num+(sum(M1[4,] < 0) == 0) +         }}} > > > #create space to store the tables > C <- array(NA, dim=c(4,2,num)) > > # list all the tables with fixed margins > num <- 0 > for (i in 1:ncol(m1)){ +     for (j in 1:ncol(m2)){ +         for (k in 1:ncol(m3)){ +             M <- t(cbind(m1[,i], m2[,j], m3[,k])) +             M1 <- rbind(M,cmg-apply(M,2,sum)) +             if (sum(M1[4,] < 0) == 0) { +                 num <- num+1 +                C[,,num] <- M1 +             } +         }}} > > C , , 1      [,1] [,2] [1,]    0    1 [2,]    0    2 [3,]    2    0 [4,]    1    0 , , 2      [,1] [,2] [1,]    0    1 [2,]    1    1 [3,]    1    1 [4,]    1    0 , , 3      [,1] [,2] [1,]    0    1 [2,]    1    1 [3,]    2    0 [4,]    0    1 , , 4      [,1] [,2] [1,]    0    1 [2,]    2    0 [3,]    0    2 [4,]    1    0 , , 5      [,1] [,2] [1,]    0    1 [2,]    2    0 [3,]    1    1 [4,]    0    1 , , 6      [,1] [,2] [1,]    1    0 [2,]    0    2 [3,]    1    1 [4,]    1    0 , , 7      [,1] [,2] [1,]    1    0 [2,]    0    2 [3,]    2    0 [4,]    0    1 , , 8      [,1] [,2] [1,]    1    0 [2,]    1    1 [3,]    0    2 [4,]    1    0 , , 9      [,1] [,2] [1,]    1    0 [2,]    1    1 [3,]    1    1 [4,]    0    1 , , 10      [,1] [,2] [1,]    1    0 [2,]    2    0 [3,]    0    2 [4,]    0    1 ______________________________________________ [hidden email] mailing list -- To UNSUBSCRIBE and more, see 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: list contingency tables

 Don't give up on for loops entirely... some of the largest time savings in optimizing loops are achieved by managing memory effectively. [1] [1] https://www.r-bloggers.com/r-tip-use-vectormode-list-to-pre-allocate-listsOn November 8, 2018 8:05:39 PM PST, li li <[hidden email]> wrote: >Hi all, >  I am trying to list all the 4 by 2 tables with some fixed margins. >  For example, consider 4 by 2 tables with row margins 1,2,2,1 and >column margins 3,3. I was able to do it using the code below. However, >as seen below, I had to first count the total number of tables with >the specific row margins and column margins in order to create space >to store the tables. >Is there a way to skip the step of counting the number of tables? >  Also, wanted to avoid for loops as much as possible since it can be >extremely slow and inefficient. >   Thanks so much in advance for you insight and help. >       Hanna > > > >> library(gtools) >> A <- permutations(n=4,r=2,v=0:3, repeats.allowed=TRUE) >> B <- apply(A, 1, sum) >> rmg <- c(1,2,2,1) >> cmg <- c(3,3) >> m1 <- t(A[which(B==1),]) >> m2 <- t(A[which(B==2),]) >> m3 <- t(A[which(B==2),]) >> >> ##count number of tables with row margins 1,2,2,1 and column margins >3,3. >> num <- 0 >> for (i in 1:ncol(m1)){ >+     for (j in 1:ncol(m2)){ >+         for (k in 1:ncol(m3)){ >+             M <- t(cbind(m1[,i], m2[,j], m3[,k])) >+             M1 <- rbind(M, cmg-apply(M,2,sum)) >+             num <- num+(sum(M1[4,] < 0) == 0) >+         }}} >> >> >> #create space to store the tables >> C <- array(NA, dim=c(4,2,num)) >> >> # list all the tables with fixed margins >> num <- 0 >> for (i in 1:ncol(m1)){ >+     for (j in 1:ncol(m2)){ >+         for (k in 1:ncol(m3)){ >+             M <- t(cbind(m1[,i], m2[,j], m3[,k])) >+             M1 <- rbind(M,cmg-apply(M,2,sum)) >+             if (sum(M1[4,] < 0) == 0) { >+                 num <- num+1 >+                C[,,num] <- M1 >+             } >+         }}} >> >> C >, , 1 > >     [,1] [,2] >[1,]    0    1 >[2,]    0    2 >[3,]    2    0 >[4,]    1    0 > >, , 2 > >     [,1] [,2] >[1,]    0    1 >[2,]    1    1 >[3,]    1    1 >[4,]    1    0 > >, , 3 > >     [,1] [,2] >[1,]    0    1 >[2,]    1    1 >[3,]    2    0 >[4,]    0    1 > >, , 4 > >     [,1] [,2] >[1,]    0    1 >[2,]    2    0 >[3,]    0    2 >[4,]    1    0 > >, , 5 > >     [,1] [,2] >[1,]    0    1 >[2,]    2    0 >[3,]    1    1 >[4,]    0    1 > >, , 6 > >     [,1] [,2] >[1,]    1    0 >[2,]    0    2 >[3,]    1    1 >[4,]    1    0 > >, , 7 > >     [,1] [,2] >[1,]    1    0 >[2,]    0    2 >[3,]    2    0 >[4,]    0    1 > >, , 8 > >     [,1] [,2] >[1,]    1    0 >[2,]    1    1 >[3,]    0    2 >[4,]    1    0 > >, , 9 > >     [,1] [,2] >[1,]    1    0 >[2,]    1    1 >[3,]    1    1 >[4,]    0    1 > >, , 10 > >     [,1] [,2] >[1,]    1    0 >[2,]    2    0 >[3,]    0    2 >[4,]    0    1 > >______________________________________________ >[hidden email] mailing list -- To UNSUBSCRIBE and more, see >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. -- Sent from my phone. Please excuse my brevity. ______________________________________________ [hidden email] mailing list -- To UNSUBSCRIBE and more, see 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.