如何对文本文件中的两个不同时期进行子集化？

Question

我有一个包含两年数据的文本文件，我想从中提取两个不同的时期（每年 7 月到 9 月）

读取文件：

   wg=read.table("C:\Users\ERIE.txt", sep ='' , header =TRUE)
   head(wg)
          Year day hour mint valu1 valu2       date
   105169 2008   1    7   30 0.045 0.014 2008-01-01
   105217 2008   2    7   30 0.046 0.015 2008-01-02
   105265 2008   3    7   30 0.043 0.013 2008-01-03

现在子集：

wg= subset(wg, wg$date >= "2008-07-01" & wg$date <= "2008-09-30" & wg$date >=  "2009-07-01" & wg$date <= "2009-09-30")
 > wg
 [1] Year  day   hour  mint  valu1 valu2 date 
 <0 rows> (or 0-length row.names)
 wg= subset(wg, date >= "2008-07-01" & date <= "2008-09-30" & date >=  "2009-07-01" & date <= "2009-09-30")
  > wg
  [1] Year  day   hour  mint  valu1 valu2 date 
   <0 rows> (or 0-length row.names)

知道为什么它不起作用

Answer 1

#one way is to use `filter` from `dplyr` package (and assuming Date is already in Date format)
library(dplyr)
wg %>%
filter(year %in% c(2008,2009) & months(Date) %in% c("July","August","September")

#If you want to stick to subset, replace second & with |:

subset(wg, date >= "2008-07-01" & date <= "2008-09-30" | date >= "2009-07-01" & date <= "2009-09-30")

Answer 2

Edit：正如 Metrics 所指出的，您的代码中有一个 & 而不是 |。这是一个可重现的示例，显示如何 select 或使用 subset:

排除范围内的日期

> mydat <- data.frame(dat = seq(as.Date("2015-01-01"), as.Date("2015-01-15"), by = "days"), x = "x")
> mydat
          dat x
1  2015-01-01 x
2  2015-01-02 x
3  2015-01-03 x
4  2015-01-04 x
5  2015-01-05 x
6  2015-01-06 x
7  2015-01-07 x
8  2015-01-08 x
9  2015-01-09 x
10 2015-01-10 x
11 2015-01-11 x
12 2015-01-12 x
13 2015-01-13 x
14 2015-01-14 x
15 2015-01-15 x
> subset(mydat, (dat >= "2015-01-05" & dat <= "2015-01-08") | (dat >= "2015-01-11" & dat <= "2015-01-13"))
          dat x
5  2015-01-05 x
6  2015-01-06 x
7  2015-01-07 x
8  2015-01-08 x
11 2015-01-11 x
12 2015-01-12 x
13 2015-01-13 x
> subset(mydat, !((dat >= "2015-01-05" & dat <= "2015-01-08") | (dat >= "2015-01-11" & dat <= "2015-01-13")))
          dat x
1  2015-01-01 x
2  2015-01-02 x
3  2015-01-03 x
4  2015-01-04 x
9  2015-01-09 x
10 2015-01-10 x
14 2015-01-14 x
15 2015-01-15 x

如何对文本文件中的两个不同时期进行子集化？

How to subset two different periods in a text file?

text

r

subset