具有多个条件的子集行

Question

我想要创建一个dataframe，它通过样本标识信息(包括Sample_Type和浓度)为每个标记创建一个在高度列中设置最大值的行。我在下面贴了一个样本数据。本例中的最终df应该包含2-4行。

structure(list(Marker = c("A", "A", "B", "B", "B", "B", "C", 
"A", "A", "A"), Height = c(40L, 61L, 38L, 33L, 49L, 114L, 152L, 
108L, 108L, 50L), Sample_Type = c("NTC", "NTC", "NTC", "NTC", 
"NTC", "NTC", "NTC", "CEPH", "CEPH", "CEPH"), Concentration = c(100L, 
100L, 100L, 100L, 100L, 100L, 100L, 100L, 50L, 50L), PCR_Protocol = 
c("Current_PCR", 
"Current_PCR", "Current_PCR", "Current_PCR", "Current_PCR", "Current_PCR", 
"Current_PCR", "Current_PCR", "Current_PCR", "Current_PCR")), class = 
"data.frame", row.names = c(NA, 
-10L))

谢谢!

Answer 1

使用dplyr，对max进行筛选：

library(dplyr)

df1 %>% 
  group_by(Marker) %>% 
  filter(max(Height) == Height)
# # A tibble: 3 x 6
# # Groups:   Marker [3]
#   Marker  Size Height Sample_Type Concentration PCR_Protocol
#   <chr>  <dbl>  <int> <chr>               <int> <chr>       
# 1 A       79.2     61 NTC                   100 Current_PCR 
# 2 B       84.2     38 NTC                   100 Current_PCR 
# 3 C       99.7     33 NTC                   100 Current_PCR