找到最小值和最大值以及R中

Question

每個唯一標識符（分組元素）創建這些列我有以下數據集：

MC <- c(rep("OS000348",8), rep("OS000361",13), rep("OS000375",5)) 
ASN <- c(rep(2,8), rep(3,5), rep(2,8), rep(3,5)) 
Dia <- c(870,"NA", 867.3, "NA", "NA", 890.3,"NA","NA",871.2,"NA",868.7,"NA",866.2, "NA", 
"NA",851,"NA","NA",842,"NA","NA",880,860,851.8,"NA",841) 

df <- data.frame(MC,ASN,Dia) 

df 

我想找到每個MC，最小和最大直徑值和設置在所得的表如下所示：

MC   Dia  Min_Dia Max_Dia 
OS000348 870  867.3 890.3 
OS000361 871.2 841  871.2 
OS000375 880  841  880 

我試圖使用dplyr包和以下：

result1 <- 
    df %>% 
    group_by(MC) %>% 
    arrange(MC) %>% 
    slice(c(1, n())) %>% 
    mutate(minmax = c("Min", "Max")) %>% 
    gather(var, val, Dia) %>% 
    unite(key, minmax, var) %>% 
    spread(key, val) 

但我沒有得到表，我想要的方式（上表第二張表）。

可以選擇嗎？

Answer 1

首先，您需要輸入NA作爲NA而不是"NA"，否則R將其讀作字符向量，並且您不能使用min()函數。這段代碼產生所需的輸出：

MC <- c(rep("OS000348",8), rep("OS000361",13), rep("OS000375",5)) 
ASN <- c(rep(2,8), rep(3,5), rep(2,8), rep(3,5)) 
Dia <- c(870,NA, 867.3, NA, NA, 890.3,NA,NA,871.2,NA,868.7,NA,866.2, NA, 
     NA,851,NA,NA,842,NA,NA,880,860,851.8,NA,841) 

df <- data.frame(MC,ASN,Dia) 

library(dplyr) 

df <- df %>% 
    group_by(MC) %>% 
    mutate(minDia=min(Dia, na.rm=T), maxDia=max(Dia, na.rm=T)) 

如果使用這個你只是想保持MC的一個觀察：

df2 <- df %>% 
    group_by(MC) %>% 
    mutate(minDia=min(Dia, na.rm=T), maxDia=max(Dia, na.rm=T)) %>% 
    ungroup() %>% 
    distinct(MC, minDia, maxDia)