如何得到如下数据框或矩阵

1. can <- c(rep(1, times = 231), rep(0, times = 178), rep(1, times = 11),
   
2.          rep(0, times = 38))
   
3. smk <- c(rep(1, times = 225), rep(0, times = 6), rep(1, times = 166),
   
4.          rep(0, times = 12), rep(1, times = 8), rep(0, times = 3), rep(1, times = 18),
   
5.          rep(0, times = 20))
   
6. alc <- c(rep(1, times = 409), rep(0, times = 49))
   
7. dat <- as.data.frame(cbind(alc, smk, can))

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希望得到如下数据框或矩阵
smk alc  can=1 can=0
0     0     频数    频数
1     0     频数    频数
0     1     频数    频数
1     1     频数    频数

谢谢！

1. table <- as.data.frame(ftable(xtabs(~ smk + alc + can)))
   
2. 
   
3. merge(with(table[table$can == 0, ], data.frame(alc = alc, smk = smk, can0 = Freq)), with(table[table$can == 1, ], data.frame(alc = alc, smk = smk, can1 = Freq)))[, c(2, 1, 3, 4)]

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1. table <- as.data.frame(ftable(xtabs(~ alc + smk + can)))
   
2. 
   
3. merge(with(table[table$can == 0, ], data.frame(alc = alc, smk = smk, "can=0" = Freq)), with(table[table$can == 1, ], data.frame(alc = alc, smk = smk, "can=1" = Freq)))[, c(2, 1, 3, 4)]

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1. table <- as.data.frame(ftable(xtabs(~ alc + smk + can)))
   
2. 
   
3. merge(with(table[table$can == 0, ], data.frame(alc = alc, smk = smk, "can=0" = Freq)), with(table[table$can == 1, ], data.frame(alc = alc, smk = smk, "can=1" = Freq)))[, c(2, 1, 3, 4)]

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1. n<-length(can);can1<-sum(can)/n;can0<-1-can1
   
2. ##矩阵
   
3. A<-cbind(smk,alc,can1,can0)
   
4. colnames(A)[3:4]<-c("can=1","can=0");A
   
5. ##数据框
   
6. B<-data.frame(smk,alc,"can=1"=can1,"can=0"=can0);B

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