有一個資料框'ori_data'（作為影像'灰色區域'），如何添加兩個變數'final_price/final_price_from'？
1.'final_price'從'price1:price4'中檢索第一個出現的數字
2.'final_price_from'是'final_price'來自變數'price1:price4'的源標簽
ori_data <- data.frame(category=c("a","b","c","d","e","f","g","h","i"),
price1=c(1,9,0,0,0,0,6,9,0),
price2=c(3,0,2,0,6,0,0,9,0),
price3=c(0,2,0,3,0,5,4,0,0),
price4=c(0,0,3,0,5,7,0,0,0))
uj5u.com熱心網友回復：
你可以試試
library(dplyr)
library(reshape2)
final_price <- ori_data %>%
melt(id.vars = "category") %>%
group_by(category) %>% arrange(category) %>%
slice(which.max(value > 0))
names(final_price)[2:3] <- c("final_price_from", "final_price")
ori_data %>%
left_join(final_price, by = "category") %>%
mutate(final_price = ifelse(final_price>0, final_price, "none"))
category price1 price2 price3 price4 final_price_from final_price
1 a 1 3 0 0 price1 1
2 b 9 0 2 0 price1 9
3 c 0 2 0 3 price2 2
4 d 0 0 3 0 price3 3
5 e 0 6 0 5 price2 6
6 f 0 0 5 7 price3 5
7 g 6 0 4 0 price1 6
8 h 9 9 0 0 price1 9
9 i 0 0 0 0 price1 none
uj5u.com熱心網友回復：
library(tidyverse)
ori_data %>%
left_join(pivot_longer(.,-category)%>%
group_by(category) %>%
summarise(s = row_number()[value > 0][1],
final_price_from = replace_na(name[s], 'none'),
final_price = replace_na(value[s], 0))) %>%
select(-s)
category price1 price2 price3 price4 final_price_from final_price
1 a 1 3 0 0 price1 1
2 b 9 0 2 0 price1 9
3 c 0 2 0 3 price2 2
4 d 0 0 3 0 price3 3
5 e 0 6 0 5 price2 6
6 f 0 0 5 7 price3 5
7 g 6 0 4 0 price1 6
8 h 9 9 0 0 price1 9
9 i 0 0 0 0 none 0
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