小编Nou*_*ura的帖子

我有一个数据框:

dt <- read.table(text = "
350 16 
366 11 
376  0
380  0
397  0
398 45  
400 19  
402 0
510 0
525 0
537 0
549 0
569 112
578 99")

我想删除第二列中除零非零值之前和之后的行的所有行.

结果将是:

dt1 <- read.table(text = "
350 16 
366 11 
376  0
397  0
398 45  
400 19  
402 0
549 0
569 112
578 99")

我有一个矩阵

mat <- matrix(c(64,76,0,0,78,35,45,0,0,4,37,0,66,46,0,0,0,0,3,0,71,0,28,97,0,30,55,65,116,30,18,0,0,143,99,0,0,0,0,0), nrow=4, byrow=T)

mat
     [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
[1,]   64   76    0    0   78   35   45    0    0     4
[2,]   37    0   66   46    0    0    0    0    3     0
[3,]   71    0   28   97    0   30   55   65  116    30
[4,]   18    0    0  143   99    0    0    0    0     0

我想创建一个列表,该列表计算非零值之间的零出现次数

[[1]]
[1] 2 2

[[2]]
[1] 1 4 1

[[3]]
[1] 1 1

[[4]]
[1] 2 5