R Studio 中有没有一种方法可以根据另一列中的值对一列求和

Question

我想要“当 mat_Source 列 = ark 时对长度列求和”，并且能够对 mat_source 列中的每个值执行此操作，以了解每个源的长度。

我查看了互联网上提出的有关汇总数据的其他问题，它们很相似，但不完全是我想要的

Answer 1

使用

dplyr

包。请注意，在运行此代码之前，您需要安装

dplyr

：

library(dplyr)

# Your data
df <- structure(list(asset_ID = 1:16, length = c(500L, 170L, 480L, 
284L, 30L, 500L, 270L, 476L, 395L, 80L, 500L, 500L, 500L, 110L, 
500L, 363L), age = c(6, 6, 9, 10, 4, 3.09589, 6.79726, 3, 5, 
18.90411, 14, 6, 22, 2, 14, 2), mat_source = c("ark", "bg", 
"brnl", "brnl", "bg", "brnl", "brnl", "ark", "brnl", "ark", "brnl", 
"ark", "ark", "brnl", "brnl", "brnl"), con_num = c(1L, 1L, 2L, 
2L, 3L, 1L, 4L, 4L, 1L, 2L, 1L, 1L, 4L, 3L, 1L, 4L)), class = "data.frame", row.names = c(NA, 
-16L))

# Result
result <- df %>%
  group_by(mat_source) %>%
  summarise(sum_length = sum(length))

result
# A tibble: 3 × 2
  mat_source sum_length
  <chr>           <int>
1 ark              2056
2 bg                200
3 brnl             3402