我的df
> df <- data.frame(food = c("fruit banana", "fruit apple", "fruit grape", "bread", "meat"), sold = rnorm(5, 100))
> df
food sold
1 fruit banana 99.47171
2 fruit apple 99.40878
3 fruit grape 99.28727
4 bread 99.15934
5 meat 100.53438
现在,我想替换以“水果”开头的食物中的所有值,然后按食物分组并汇总已售金额和已售金额。
> df %>%
+ mutate(food = replace(food, str_detect(food, "fruit"), "fruit")) %>%
+ group_by(food) %>%
+ summarise(sold = sum(sold))
Source: local data frame [3 x 2]
food sold
(fctr) (dbl)
1 bread 99.15934
2 meat 100.53438
3 NA 298.16776
为什么此命令不起作用?它给我NA而不是水果?
最佳答案
它对我有用,我认为您的数据有以下因素:
在按如下所示进行数据处理时使用stringsAsFactors=FALSE
,或者您可以在R环境中运行options(stringsAsFactors=FALSE)
以避免相同的情况:
df <- data.frame(food = c("fruit banana", "fruit apple", "fruit grape", "bread", "meat"), sold = rnorm(5, 100),stringsAsFactors = FALSE)
df %>%
mutate(food = replace(food, str_detect(food, "fruit"), "fruit")) %>%
group_by(food) %>%
summarise(sold = sum(sold))
输出:
# A tibble: 3 × 2
food sold
<chr> <dbl>
1 bread 99.67661
2 fruit 300.28520
3 meat 99.88566
关于r - 使用dplyr和stringr替换所有值始于,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/43778696/