Question

如何抑制（不打印）行号？
代码如下：

dd<-data.frame(a=gl(2,3),b=gl(3,1,6) ) 
model.matrix( ~a + b + a*b, dd )

尝试：

> dd<-data.frame(a=gl(2,3),b=gl(3,1,6) ) 
> model.matrix( ~a + b + a*b, dd )
  (Intercept) a2 b2 b3 a2:b2 a2:b3
1           1  0  0  0     0     0
2           1  0  1  0     0     0
3           1  0  0  1     0     0
4           1  1  0  0     0     0
5           1  1  1  0     1     0
6           1  1  0  1     0     1
attr(,"assign")
[1] 0 1 2 2 3 3
attr(,"contrasts")
attr(,"contrasts")$a
[1] "contr.treatment"
attr(,"contrasts")$b
[1] "contr.treatment"

> cat(model.matrix( ~a + b + a*b, dd ))
1 1 1 1 1 1 0 0 0 1 1 1 0 1 0 0 1 0 0 0 1 0 0 1 0 0 0 0 1 0 0 0 0 0 0 1
> model.matrix( ~ a + b + a*b, dd )
  (Intercept) a2 b2 b3 a2:b2 a2:b3
1           1  0  0  0     0     0
2           1  0  1  0     0     0
3           1  0  0  1     0     0
4           1  1  0  0     0     0
5           1  1  1  0     1     0
6           1  1  0  1     0     1
attr(,"assign")
[1] 0 1 2 2 3 3
attr(,"contrasts")
attr(,"contrasts")$a
[1] "contr.treatment"
attr(,"contrasts")$b
[1] "contr.treatment"

> dd<-data.frame(a=gl(2,3),b=gl(3,1,6) )
> print(model.matrix( ~a + b + a*b, dd , rowNames=False))
  (Intercept) a2 b2 b3 a2:b2 a2:b3
1           1  0  0  0     0     0
2           1  0  1  0     0     0
3           1  0  0  1     0     0
4           1  1  0  0     0     0
5           1  1  1  0     1     0
6           1  1  0  1     0     1
attr(,"assign")
[1] 0 1 2 2 3 3
attr(,"contrasts")
attr(,"contrasts")$a
[1] "contr.treatment"
attr(,"contrasts")$b
[1] "contr.treatment"

> print(model.matrix( ~a + b + a*b, dd , colNames=False))
  (Intercept) a2 b2 b3 a2:b2 a2:b3
1           1  0  0  0     0     0
2           1  0  1  0     0     0
3           1  0  0  1     0     0
4           1  1  0  0     0     0
5           1  1  1  0     1     0
6           1  1  0  1     0     1
attr(,"assign")
[1] 0 1 2 2 3 3
attr(,"contrasts")
attr(,"contrasts")$a
[1] "contr.treatment"
attr(,"contrasts")$b
[1] "contr.treatment"

Answer 1

不幸的是，在打印矩阵时似乎没有任何方法可以抑制行名称，不是吗？一种选择是强制使用data.frame并使用print.data.frame()的row.names参数：

dd <- data.frame(a=gl(2,3),b=gl(3,1,6));
print(as.data.frame(model.matrix( ~a + b + a*b, dd )),row.names=F);
##  (Intercept) a2 b2 b3 a2:b2 a2:b3
##            1  0  0  0     0     0
##            1  0  1  0     0     0
##            1  0  0  1     0     0
##            1  1  0  0     0     0
##            1  1  1  0     1     0
##            1  1  0  1     0     1

Answer 2

您可以保存model.matrix的结果，然后将rownames更改为空字符。

dd<-data.frame(a=gl(2,3),b=gl(3,1,6) ) 
mm <- model.matrix( ~a + b + a*b, dd )
mm

#  (Intercept) a2 b2 b3 a2:b2 a2:b3
#1           1  0  0  0     0     0
#2           1  0  1  0     0     0
#3           1  0  0  1     0     0
#4           1  1  0  0     0     0
#5           1  1  1  0     1     0
#6           1  1  0  1     0     1
#attr(,"assign")
#[1] 0 1 2 2 3 3
#attr(,"contrasts")
#attr(,"contrasts")$a
#[1] "contr.treatment"

#attr(,"contrasts")$b
#[1] "contr.treatment"

rownames(mm) <- rep("", 6)
#rownames(mm) <- rep("", nrow(mm)) #more general
mm

# (Intercept) a2 b2 b3 a2:b2 a2:b3
#           1  0  0  0     0     0
#           1  0  1  0     0     0
#           1  0  0  1     0     0
#           1  1  0  0     0     0
#           1  1  1  0     1     0
#           1  1  0  1     0     1
#attr(,"assign")
#[1] 0 1 2 2 3 3
#attr(,"contrasts")
#attr(,"contrasts")$a
#[1] "contr.treatment"

#attr(,"contrasts")$b
#[1] "contr.treatment"

Answer 3

没有print.matrix方法，所以要咨询的相应帮助页面是?print.default，其中没有用于抑制行名或列名的参数，所以我建议像这样：

 ( matrix( model.matrix( ~a + b + a*b, dd ) , nrow(dd)) )
     [,1] [,2] [,3] [,4] [,5] [,6]
[1,]    1    0    0    0    0    0
[2,]    1    0    1    0    0    0
[3,]    1    0    0    1    0    0
[4,]    1    1    0    0    0    0
[5,]    1    1    1    0    1    0
[6,]    1    1    0    1    0    1

另一种选择是构建一个按照您的需要执行的功能，如果您只想抑制rownames或colnames，您可以使逻辑更精细：

> print.noRowCol <- function(x) {dimnames(x)<- NULL; print(x)}
> print.noRowCol (model.matrix( ~a + b + a*b, dd ) )
     [,1] [,2] [,3] [,4] [,5] [,6]
[1,]    1    0    0    0    0    0
[2,]    1    0    1    0    0    0
[3,]    1    0    0    1    0    0
[4,]    1    1    0    0    0    0
[5,]    1    1    1    0    1    0
[6,]    1    1    0    1    0    1
attr(,"assign")
[1] 0 1 2 2 3 3
attr(,"contrasts")
attr(,"contrasts")$a
[1] "contr.treatment"

attr(,"contrasts")$b
[1] "contr.treatment"

如何抑制（不打印）行号？

3 个答案: