r - 根据条件合并 R 中的行和值

Question

我有以下示例数据:

# data
school = c('ABC University','ABC Uni','DFG University','DFG U')
applicant = c(2000,3100,210,2000)
students = c(100,2000,300,4000)
df = data.frame(school,applicant,students)

我想合并到这个:

|school        |appliant| students |
-----------------------------------
|ABC University| 5100   | 2100     |
|DFG University| 2210   | 4300     |

我运行了这段代码:

df$school[df$school == 'ABC Uni'] = 'ABC University'

但它给了我两次 ABC 大学，而不是将它们合并在一起。

Answer 1

这实际上取决于其余的字符串，但您可以查看 grep 并使用 ^ 开始。

df[grep('^ABC U', df$school), 'school'] <- 'ABC University'
df[grep('^DFG U', df$school), 'school'] <- 'DFG University'

和往常一样聚合。

aggregate(cbind(applicant, students) ~ school, df, sum)
#           school applicant students
# 1 ABC University      5100     2100
# 2 DFG University      2210     4300