从一个data.frame中查找值，使用当前data.frame中的日期在另一个data.frame中创建列

我正在尝试从一个data.frame中选择要导入到另一个data.frame的列中的信息。要选择的值可以按行和列标识，并且取决于output data.frame现有列的计算。我被卡住了，因为有很多步骤需要组合，尽管我已经把它分解并准备好了零件，但我无法将最终的组合组合在一起

我的查找data.frame的格式如下：

Date.Time <- rep(c("2014/05/06_pm", "2014/05/07_am", "2014/05/07_pm", "2014/05/08_am"), 4)
Nest <- c(rep("WTSN08", 4), rep("WTSN26", 4), rep("WTSN07", 4), rep("WTSN06", 4))
value <- c(25, 24, 26, 25, 27, 27, 28, 26, 21, 23, 21, 20, 25, 28, 26, 28)
df <- data.frame(Date.Time, Nest, value)
library(reshape)
Lookup <- cast(df, Nest ~ Date.Time, row.names = FALSE)

Nest <- rep(c("WTSN08","WTSN26","WTSN07","WTSN06"), 2)
Hatch <- as.Date(rep(c("2014/04/28", "2014/04/29", "2014/04/29", "2014/04/25"),2))
Age <- c(9.5, 8.0, 8.5, 13.0, 10.0, 9.5, 9.5, 12.0)
Output <- data.frame(Nest, Hatch, Age)

将输出正确的日期，并且

paste(as.character(Output$Hatch + Output$Age), "am", sep = "_")

将在日期后附加“_am”，以便可以这样查找值

Lookup[Lookup$Nest == "WTSN08",as.character(paste(as.character(Output$Hatch + Output$Age), "am", sep = "_"))]

那

grepl("^.+(.5)$",Output$Age)

将返回以“.5”结尾的年龄位置

我尝试将其封装在ifelse命令中，最初只是为了获得计算的时间段的值（而不是担心减去天数），以形成列：

Output$T <- ifelse(grepl("^.+(.5)$",WTS_w$Age),
    Max.Ts[Max.Ts$Nest == as.character(WTS_w$Nest), paste(as.character(WTS_w$Hatch + WTS_w$Age), "pm", sep = "_")],
    Max.Ts[Max.Ts$Nest == as.character(WTS_w$Nest), paste(as.character(WTS_w$Hatch + WTS_w$Age), "am", sep = "_")]
)

---

Output$T我认为让用户知道我已经解决了这个问题可能会有帮助

最后，我将
查找
data.frame保留为熔化的形式，即：

df <- data.frame(Date.Time, Nest, value)

这样，在我已经实现的添加之后，它们可以与
输出
data.frame匹配

将其与包装在
match
中的
ifelse
命令结合起来，给出了当前时间段的值：

Output$T <- df$value[match(ifelse(grepl("^.+(.5)$",Output$Age),
                                  paste(Output$Nest, as.character(Output$Hatch + Output$Age), "pm", sep = "_"),
                                  paste(Output$Nest, as.character(Output$Hatch + Output$Age), "am", sep = "_"))
                                  ,paste(df$Nest, df$Date.Time, sep = "_"))]

输出$T
paste(df$Nest, df$Date.Time, sep = "_")

Output$T <- df$value[match(ifelse(grepl("^.+(.5)$",Output$Age),
                                  paste(Output$Nest, as.character(Output$Hatch + Output$Age), "pm", sep = "_"),
                                  paste(Output$Nest, as.character(Output$Hatch + Output$Age), "am", sep = "_"))
                                  ,paste(df$Nest, df$Date.Time, sep = "_"))]

Output$T1 <- df$value[match(ifelse(grepl("^.+(.5)$",Output$Age),
                                   paste(Output$Nest, as.character(Output$Hatch + Output$Age), "am", sep = "_"),
                                   paste(Output$Nest, as.character(Output$Hatch + Output$Age -1), "pm", sep = "_"))
                                   ,paste(df$Nest, df$Date.Time, sep = "_"))]