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假设我有一个小矩阵列表，并且想要提取每个矩阵的加入。attr()除了循环函数之外，有什么好的方法可以做到这一点。

矩阵数据：

tfmatrx<-list(

MA0275.1 = structure(c(0, 76, 0, 24, 0, 100, 0, 0, 0, 0, 
                       100, 0, 0, 0, 100, 0, 72, 11, 16, 0, 53, 0, 0, 47), .Dim = c(4L, 
                                                                                    6L), .Dimnames = list(c("A", "C", "G", "T"), NULL), id = "MA0275.1", accession = "ASG1"), 
MA0276.1 = structure(c(0, 220, 8, 35, 0, 291, 0, 3, 61, 21, 
                       133, 10, 58, 54, 101, 12, 130, 0, 54, 0, 0, 11, 8, 147, 33, 
                       150, 8, 35, 80, 0, 92, 26, 0, 8, 249, 19, 0, 0, 256, 18), .Dim = c(4L, 
                                                                                          10L), .Dimnames = list(c("A", "C", "G", "T"), NULL), id = "MA0276.1", accession = "ASH1"), 
MA0277.1 = structure(c(63, 13, 13, 13, 100, 0, 0, 0, 100, 
                       0, 0, 0, 88, 13, 0, 0, 75, 0, 25, 0, 0, 0, 100, 0, 78, 16, 
                       3, 3, 81, 6, 6, 6, 63, 13, 13, 13), .Dim = c(4L, 9L), .Dimnames = list(
                         c("A", "C", "G", "T"), NULL), id = "MA0277.1", accession = "AZF1"), 
MA0278.1 = structure(c(64, 217, 425, 292, 104, 552, 150, 
                       192, 484, 111, 114, 288, 78, 401, 186, 333, 455, 51, 370, 
                       122, 248, 34, 670, 46, 98, 724, 143, 33, 52, 918, 7, 20, 
                       348, 346, 280, 24, 12, 3, 977, 6, 966, 5, 23, 4, 26, 6, 962, 
                       4, 9, 10, 4, 975, 47, 930, 7, 15, 892, 42, 16, 49, 487, 123, 
                       320, 68, 288, 140, 317, 254, 373, 110, 81, 434, 178, 367, 
                       184, 268, 402, 140, 341, 114, 435, 229, 241, 94), .Dim = c(4L, 
                                                                                  21L), .Dimnames = list(c("A", "C", "G", "T"), NULL), id = "MA0278.1", accession = "BAS1"))

我想在字符向量或 data.frame 中获取所有加入。我知道如何对列表中的第一个元素执行此操作，但是如何对所有加入项执行此操作？

我想在这里实现的输出是：

ASG1
ASH1
ASF1
BAS1

names(tfmatrix)提供所有名称，但不提供加入，任何帮助表示赞赏。

4

1 回答 1

10

怎么样

lapply(tfmatrx, attr, "accession")
$MA0275.1
[1] "ASG1"

$MA0276.1
[1] "ASH1"

$MA0277.1
[1] "AZF1"

$MA0278.1
[1] "BAS1"

您也可以使用sapply，这很方便，因为输出是一个向量（sapply 尝试尽可能简化结果）。

sapply(tfmatrx, attr, "accession")
MA0275.1 MA0276.1 MA0277.1 MA0278.1 
  "ASG1"   "ASH1"   "AZF1"   "BAS1"

这相当于上面未列出的lapply解决方案。

unlist(lapply(tfmatrx, attr, "accession"))
MA0275.1 MA0276.1 MA0277.1 MA0278.1 
  "ASG1"   "ASH1"   "AZF1"   "BAS1"
于 2013-03-06T10:23:18.793 回答