Question

我有一个名为mydf的数据框。 Sample列中有重复的样本。我想提取最大total_reads的唯一样本行并获取result。

mydf<-structure(list(Sample = c("AOGC-02-0188", "AOGC-02-0191", "AOGC-02-0191", 
"AOGC-02-0191", "AOGC-02-0194", "AOGC-02-0194", "AOGC-02-0194"
), total_reads = c(27392583, 19206920, 34462563, 53669483, 24731988, 
43419826, 68151814), Lane = c("4", "5", "4", "4;5", "5", "4", 
"4;5")), .Names = c("Sample", "total_reads", "Lane"), row.names = c("166", 
"169", "170", "171", "173", "174", "175"), class = "data.frame")

结果

  Sample        total_reads  Lane
 AOGC-02-0188    27392583    4
 AOGC-02-0191    53669483  4;5
 AOGC-02-0194    68151814  4;5

Answer 1

您可以aggregate然后merge，

merge(aggregate(total_reads ~ Sample, mydf, max), mydf)
#        Sample total_reads Lane
#1 AOGC-02-0188    27392583    4
#2 AOGC-02-0191    53669483  4;5
#3 AOGC-02-0194    68151814  4;5

Answer 2

我们可以使用data.table。转换＆＃39; data.frame＆＃39;到＆＃39; data.table＆＃39; （setDT(mydf)），按＆＃34;示例＆＃34;，order＆＃39; total_reads＆＃39;使用head对第一次观察进行依次推断和分组。

library(data.table)
setDT(mydf)[order(-total_reads), head(.SD, 1) , Sample]

Answer 3

使用mydf %>% group_by(Sample) %>% # for each unique sample arrange(-total_reads) %>% # order by total_reads DESC slice(1) # select the first row, i.e. with highest total_reads包，你可以这样做：

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在R数据帧的另一列中提取具有最大值的唯一行

3 个答案: