library(lubridate)
library(tidyverse)
datetime <- seq(
from = as.POSIXct("2012-1-1 0:29:05", tz = "Canada/Mountain"),
to = as.POSIXct("2012-2-1 0:29:05", tz = "Canada/Mountain"),
by = "hour"
)
f <- runif(745, min = 0, max =2) #variable f
df <- data.frame(datetime, f)
# method using fill function from tidyr package
df2 <- df %>%
mutate(Date = as.Date(datetime, tz = "Canada/Mountain")) %>%
left_join( #this will grab the f value at 0:29:05 of each day
df %>% filter(hour(datetime) == 0) %>% select(datetime, Fn = f),
by = 'datetime'
) %>%
group_by(Date) %>%
fill(Fn, Fn, .direction = 'down') %>% #fills in NA values with f values of the following day
mutate(
Z = ( Fn - f ) / Fn
) %>%
ungroup() %>%
select(-Date)
# method not using fill
df3 <- df %>%
mutate(Date = as.Date(datetime, tz = "Canada/Mountain")) %>%
left_join( #this will grab the f value at 0:29:05 of each day
df %>% filter(hour(datetime) == 0) %>% select(datetime, Fn = f),
by = 'datetime'
) %>%
group_by(Date) %>%
mutate(
Fn = na.omit(Fn),
Z = ( Fn - f ) / Fn
) %>%
ungroup() %>%
select(-Date)
# both methods result in the same result, as shown below
# A tibble: 745 x 4
datetime f Fn Z
<dttm> <dbl> <dbl> <dbl>
1 2012-01-01 00:29:05 0.590 0.590 0
2 2012-01-01 01:29:05 1.57 0.590 -1.66
3 2012-01-01 02:29:05 0.537 0.590 0.0900
4 2012-01-01 03:29:05 0.691 0.590 -0.171
5 2012-01-01 04:29:05 0.719 0.590 -0.218
6 2012-01-01 05:29:05 0.811 0.590 -0.374
7 2012-01-01 06:29:05 0.248 0.590 0.581
8 2012-01-01 07:29:05 1.98 0.590 -2.35
9 2012-01-01 08:29:05 0.839 0.590 -0.422
10 2012-01-01 09:29:05 0.733 0.590 -0.242
# ... with 735 more rows
只是一个想法,但你不应该说出R对象的名字
F
因为它通常是为
FALSE
价值观。
