Question

我有一个这样的数据框。

ID <- c("111","111","111","111",
        "113","113","113","113")
ToolID <- c("CCP_A","CCP_B","CCP_B","CCQ_A",
            "CCP_A","CCP_B","CCP_B","CCQ_A")
Step <- c("Step_A","Step_B","Step_B","Step_C",
          "Step_A","Step_B","Step_B","Step_C")
Datetime <- c("2018-04-19 12:44:11","2018-04-17 12:44:11","2018-04-17 12:44:11","2018-04-16 21:11:09",
              "2018-04-13 12:44:11","2018-04-11 12:44:11","2018-04-11 12:44:11","2018-04-10 21:11:09")

df <- data.frame(ID,ToolID,Step,Datetime) 
df$Datetime <- as.POSIXct(df$Datetime,format="%Y-%m-%d %H:%M:%S")

我正在尝试创建一个新列“ New.Datetime”，它是仅在ToolID == "CCP_B" & Step=="Step_B"

下按ID分组的MAX（Datetime）。

这是我想要的输出

   ID ToolID   Step            Datetime        New.Datetime
  111  CCP_A Step_A 2018-04-19 12:44:11 2018-04-17 12:44:11
  111  CCP_B Step_B 2018-04-17 12:44:11 2018-04-17 12:44:11
  111  CCP_B Step_B 2018-04-17 12:44:11 2018-04-17 12:44:11
  111  CCQ_A Step_C 2018-04-16 21:11:09 2018-04-17 12:44:11
  113  CCP_A Step_A 2018-04-13 12:44:11 2018-04-11 12:44:11
  113  CCP_B Step_B 2018-04-11 12:44:11 2018-04-11 12:44:11
  113  CCP_B Step_B 2018-04-11 12:44:11 2018-04-11 12:44:11
  113  CCQ_A Step_C 2018-04-10 21:11:09 2018-04-11 12:44:11

我正在尝试这样做，但是new.datetime似乎与数字值杂乱无章。

library(dplyr)
df1 <- df %>%
  group_by(ID) %>%
  mutate(New.Datetime = ifelse((ToolID == "CCP_B" & Step=="Step_B"), 
                               max(Datetime), Datetime))

Answer 1

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case_when

正如评论中的OP所述，根据ecah'ID'的条件，其值为df %>% group_by(ID) %>% mutate(New.DateTime = case_when(ToolID == "CCP_B" & Step == "Step_B" ~ max(Datetime), TRUE ~ Datetime)) # A tibble: 8 x 5 # Groups: ID [2] # ID ToolID Step Datetime New.DateTime # <fct> <fct> <fct> <dttm> <dttm> #1 111 CCP_A Step_A 2018-04-19 12:44:11 2018-04-19 12:44:11 #2 111 CCP_B Step_B 2018-04-17 12:44:11 2018-04-19 12:44:11 #3 111 CCP_B Step_B 2018-04-17 12:44:11 2018-04-19 12:44:11 #4 111 CCQ_A Step_C 2018-04-16 21:11:09 2018-04-16 21:11:09 #5 113 CCP_A Step_A 2018-04-13 12:44:11 2018-04-13 12:44:11 #6 113 CCP_B Step_B 2018-04-11 12:44:11 2018-04-13 12:44:11 #7 113 CCP_B Step_B 2018-04-11 12:44:11 2018-04-13 12:44:11 #8 113 CCQ_A Step_C 2018-04-10 21:11:09 2018-04-10 21:11:09，我们只需要

max

创建一个新列，该列是日期时间的最大值，并带有其他列上的条件

1 个答案: