子集由Diel期間多天（子列由不同df的多個列組成）

我正在嘗試將遙測數據歸入死亡時期。遙測數據跨越7個月，我希望這些子集使用每日日出數據。子集由Diel期間多天（子列由不同df的多個列組成）

比方說df1是我的遙測數據，並df2是我的日出數據：

df1 <- data.frame(
    datetime = as.POSIXct(c("2016-05-01 04:30", "2016-05-01 07:00", "2016-05-01 13:50", 
        "2016-05-03 03:50", "2016-05-04 18:20", "2016-05-06-04:20")), 
    ID = c("A1", "B3", "A2", "A2", "B1", "B2") 
) 


df2 <- data.frame(
    date = as.POSIXct(c("2016-05-01", "2016-05-02", "2016-05-03", "2016-05-04", "2016-05-05", "2016-05-06")), 
    ntwilight.start = c("03:25:00", "03:23:00", "03:21:00", "03:19:00", "03:17:00", "03:15:00"), 
    sunrise = c("04:45:00", "04:44:00", "04:42:00", "04:40:00", "04:39:00", "04:37:00") 
) 
df2$ntwilight.start <- as.POSIXct(paste(df2$date, df2$ntwilight.start, sep = " "), format = "%Y-%m-%d %H:%M") 
df2$sunrise <- as.POSIXct(paste(df2$date, df2$sunrise, sep = " "), format = "%Y-%m-%d %H:%M")

爲了創建一個子集天亮，我需要從df1選取datetime下降ntwilight.start和sunrise之間的所有行從df2。然後，子集應該是這樣的：

   datetime ID 
1 2016-05-01 04:30:00 A1 
2 2016-05-03 03:50:00 A2 
3 2016-05-06 04:20:00 B2

我可以用一對時間值

dawn <- df1[df1$datetime >= as.POSIXct("2016-05-01 03:25", format = "%Y-%m-%d %H:%M") & df1$datetime < as.POSIXct("2016-05-01 04:45", format = "%Y-%m-%d %H:%M")]

但是，下面的代碼無法提供合適的匹配於子集df1：

dawn2 <- df1[df1$datetime >= df2$ntwilight.start & df1$datetime < df2$sunset,]

我該怎麼辦R搜索df2爲與日期匹配的行，並使用ap在df2中確定子集合？

我感覺好像我可能需要將日期和時間分隔成不同的列（對於兩個數據框），並且可能需要按日期將df1分組，並且將每組分組。

來源

2017-08-03 Evelyn Mac

我使用了一些魔法dplyr按日期加入您的dataframes，然後我通過

df1 <- data.frame(
datetime = as.POSIXct(c("2016-05-01 04:30", "2016-05-01 07:00", "2016-05-01 13:50", 
         "2016-05-03 03:50", "2016-05-04 18:20", "2016-05-06 04:20"), 
         , format = "%Y-%m-%d %H:%M"), 
ID = c("A1", "B3", "A2", "A2", "B1", "B2") 
) 

df1$date <- as.POSIXct(as.character(df1$datetime), format = "%Y-%m-%d") #there is probably a better way to isolate date, but this works... 


df2 <- data.frame(
date = as.POSIXct(c("2016-05-01", "2016-05-02", "2016-05-03", "2016-05-04", "2016-05-05", "2016-05-06")), 
ntwilight.start = c("03:25:00", "03:23:00", "03:21:00", "03:19:00", "03:17:00", "03:15:00"), 
sunrise = c("04:45:00", "04:44:00", "04:42:00", "04:40:00", "04:39:00", "04:37:00") 
) 

df2$ntwilight.start <- as.POSIXct(paste(df2$date, df2$ntwilight.start, sep = " "), format = "%Y-%m-%d %H:%M") 
df2$sunrise <- as.POSIXct(paste(df2$date, df2$sunrise, sep = " "), format = "%Y-%m-%d %H:%M") 



library(dplyr) 
dawn2 <- df1 %>% 
    left_join(df2,by = "date") %>%       # join the 2 data frames by date 
    filter(datetime >= ntwilight.start, datetime < sunrise) # filter datetime before twilight and after sunrise

來源

2017-08-14 18:58:48

過濾得到的數據幀，謝謝！太棒了。 –

子集由Diel期間多天（子列由不同df的多個列組成）

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