R 故障排除：根据数据框中另一列中的值对数据框中的一列的值求和

Question

I am working on my final project for my data visualization class in R and I am trying to identify minority-majority counties in the US using CDC data. For every county, I want to sum only the values in the Population column that correspond to the minority groups in the Races column.

I wrote the following code to sum the population counts of minority groups and it worked fine at first. But now the minPop column is just outputting 64590855 for every row. Any help would be greatly appreciated!

races <- c("American Indian or Alaska Native", "Asian or Pacific Islander", "Black or African American")

group_by(County.Code) %>%
   mutate(minPop = sum(subset(Population, Race %in% races))) %>%
ungroup() 

Screenshot of my data frame

Answer 1

The following seems to be what the question asks for. Untested since there is no data in useable format.

df_dem1 %>%
  filter(Race %in% races) %>%
  group_by(County.Code) %>%
  mutate(minPop = sum(Population)) %>%
  ungroup()