r - data.frame 中的发生计数

Question

我有一个这样的数据框：

 G1  G2  G3
  a   b   f
  b   c   a
  c   d   b

和参考列表： L: a b c d e f

我想要以下输出：

a: 2, G1,G3   (that is "a" occurs two times in G1 and in G3 column)
b: 3, G1,G2,G3
c: 2, G1,G2

等等..有人可以帮助我吗？很抱歉打扰你，但我是 R 的新手，提前谢谢。

埃莱奥诺拉

Answer 1

你可以这样做：

r <- reshape(d,varying=list(colnames(d)),direction='long',
             v.names='value',times=colnames(d),timevar='colname')

res <- by(r,r$value,FUN=function(x){unique(x$colname)})



> res

r$value: a
[1] "G1" "G3"
------------------------------------------------------------ 
r$value: b
[1] "G1" "G2" "G3"
------------------------------------------------------------ 
r$value: c
[1] "G1" "G2"
------------------------------------------------------------ 
r$value: d
[1] "G2"
------------------------------------------------------------ 
r$value: f
[1] "G3"

基本上res是一个包含每个字母的列表，该字母出现的列名向量，例如：

res$a : 'G1', 'G3'
res$b : 'G1', 'G2', 'G3'
...

如果您只想要出现次数，您可以执行以下操作：

> lapply(res,length)
$a
[1] 2

$b
[1] 3

$c
[1] 2

$d
[1] 1

$f
[1] 1

编辑：
要写入res文件，一种方法可能如下：

# prepare the table (data.frame) to be written
dF <- do.call(rbind.data.frame, lapply(res,function(x){list(Occur=length(x),Columns=paste(x,collapse=' '))}))
dF <- cbind(Letter=row.names(dF),dF)
# write the table to file
write.table(dF,row.names=FALSE,sep=',',file='myfile.csv')

文件文本：

"Letter","Occur","Columns"
"a",2,"G1 G3"
"b",3,"G1 G2 G3"
"c",2,"G1 G2"
"d",1,"G2"
"f",1,"G3"

Answer 2

我以另一种方式尝试过。

A=data.frame( G1=c("a","b","c"),  G2=c("b","c","d"),  G3=c("f","a","b"))

B= melt(as.matrix(A))
B$X2 =as.character(B$X2)
B1=table(as.matrix(A))
D=aggregate(X2~value , B, FUN=c)
D$cnt=B1[D$value]
D

输出是

  value         X2 cnt
1     a     G1, G3   2
2     b G1, G2, G3   3
3     c     G1, G2   2
4     d         G2   1
5     f         G3   1

Answer 3

这两种方法都已经很好地工作了。只是想我会给出一些不同的方法来解决类似的问题。

#Vinux's data:
A=data.frame( G1=c("a","b","c"),  G2=c("b","c","d"),  G3=c("f","a","b"))

B <- data.frame(x=rep(colnames(A), sapply(A, length)),        #means of reshaping data
    y=c(apply(A, 2, as.character)))
C <- split(B$x, B$y)                                          #column names by value
D <- data.frame(letter=names(C), occurance=sapply(C, length)) #get occurrences
D$column <- sapply(C, as.character)                           #force vector of vectors
D[, c(1, 3, 2), ]                                             #order it

产生：

  letter     column occurance
a      a     G1, G3         2
b      b G1, G2, G3         3
c      c     G1, G2         2
d      d         G2         1
f      f         G3         1