从每列中随机挑选元素以生成data.table的子集

Question

my_data：

LCE1B   KIR2DL4 CDC20   CC2D1B  STXBP3  LMLN    SDAD1   NPAS4
NDUFC2  KIR3DL3 IKZF2   CCT6A   TGFBR2  MMP24   PADI4   SCUBE2
SNRPD1  KRT33B  INA     CORO2A  CDKL3   SRPK1   RNF145  SLC45A4
SSNA1   MBTD1   MATN1   FAAH2           SLC9A4  TBL3
TANK            NOS1AP                  SPON1
TMEM14C                             

所需的输出：

NDUFC2  KRT33B  CDC20   CORO2A  TGFBR2  SRPK1   SDAD1  SCUBE2
TMEM14C KRT33B  INA     CC2D1B  STXBP3  SPON1   PADI4  NPAS4

我尝试使用示例

sample(1:ncol(my_data), 2, replace=FALSE)

随机选择该行。我需要从每一栏中随机挑选。

Answer 1

# create the MWE
my_data <- as.data.frame(matrix(sample(c("", letters[1:24]), 48, replace = TRUE), 6, 8))

apply(my_data, 2, function(col){
    # get non empty values
    cc <- col[col!=""]
    cc[sample(seq(cc), 2, replace=FALSE)]
})