根据条件更改 r 中的值列数据框

Question

I have a column like this:

weekday
1
5
3
6
...

I want to update these values in this way:

• 1 -> 7
• 2 -> 1
• 3 -> 2
• 4 -> 3
• 5 -> 4
• 6 -> 7
• 7 -> 6

I've tried:

df$weekday[df$weekday == 1] <- 7
df$weekday[df$weekday == 2] <- 1
df$weekday[df$weekday == 3] <- 2
df$TIC_DATE_WEEKDAY[df$weekday == 4] <- 3
df$TIC_DATE_WEEKDAY[df$weekday == 5] <- 4
df$TIC_DATE_WEEKDAY[df$weekday == 6] <- 5
df$TIC_DATE_WEEKDAY[df$weekday == 7] <- 6 

But in this way when I update a value than the others change obviously.

Answer 1

我们可以在base R做到这一点

df$TIC_DATE_WEEKDAY <- setNames(1:7, c(7, 1, 2, 3, 4, 7, 6))[as.character(df$weekday)]

Answer 2

您可以使用dplyr::recode -

df_7_tic_clean_final$TIC_DATE_WEEKDAY <- dplyr::recode(df_7_tic_clean_final$TIC_DATE_WEEKDAY, `1` = 7, `2` = 1, `3` = 2, `4` = 3, `5` = 4, `6` = 7, `7` = 6)

Answer 3

Maybe you can try this

# lookup table
> v <- 1:7
> lut <- c(tail(v, 1), head(v, -1))

# dummy data
> x <- c(1, 2, 5, 3, 4, 2, 7)

# mapping from `lut` and `v`
> lut[match(x, v)]
[1] 7 1 4 2 3 1 6