如何对 R 中的一列求和，该列被另一列的值过滤？ 还是到特定的行？

Question

I want to find the column sum for a data set when another column is a specific value. Below is a screen grab of my data, I want to sum the farmID for each iteration.

My guess would be that the code is IF(iteration=x), sum(FarmID) but I don't know how to make that happen.

partial screenshot of data

Answer 1

An alternative would be to use library(dplyr) functions. For example you can sum the farm IDs by iteration as such:

yourdata %>% 
  group_by(Iteration) %>% 
  summarise(Farm_ID_sum = sum(Farm ID))

An example:

example <- data.frame(
   "Iteration" = sample(1:5, 20, replace = TRUE), 
   "FarmID" = sample(1:500, 20, replace = TRUE)
   )

example %>% 
   group_by(Iteration) %>% 
   summarise(Farm_ID_sum = sum(FarmID))

# Gives the output:
# A tibble: 5 x 2
  Iteration Farm_ID_sum
      <int>       <int>
1         1         790
2         2         694
3         3         391
4         4        1588
5         5        1828