Question

我创建了一个带有计数，N和百分比的摘要data.frame。摘要data.frame具有名称 - ＆gt;类别，n，计数和百分比。计数data.frame具有名称 - ＆gt;类别，数量。类别是角色。通常，计数数据框中的行将小于汇总中的行。

我在MSSQL中这样做的方式是

update summary
set summary.count = counts.count
from summary
inner join counts
on summary.category = counts.category

怎么可以在R？

中完成

支持代码。

summary <- data.frame(category=c("apples","oranges","pears"),N=10,count=0,percentage=0)
> summary
  category  N count percentage
1   apples 10     0          0
2  oranges 10     0          0
3    pears 10     0          0
> counts <- data.frame( category=c("apples","pears"), count = c(5,5) )
> counts
  category count
1   apples     5
2    pears     5

# desired outcome after processing
> summary
  category  N count percentage
1   apples 10     5          0.5
2  oranges 10     0          0
3    pears 10     5          0.5

Answer 1

我在搜索R data.frame union之后发现了merge命令。

> summary <- data.frame(category=c("apples","oranges","pears"),N=10)
> summary
  category  N
1   apples 10
2  oranges 10
3    pears 10
> counts <- data.frame( category=c("apples","pears"), count = c(5,5) )
> counts
  category count
1   apples     5
2    pears     5
> merged <- merge( summary, counts, by="category", all.x = TRUE)
> merged
  category  N count
1   apples 10     5
2  oranges 10    NA
3    pears 10     5
> merged[is.na(merged)] <- 0
> merged
  category  N count
1   apples 10     5
2  oranges 10     0
3    pears 10     5
> merged["percentage"] = merged$count / merged$N
> merged
  category  N count percentage
1   apples 10     5        0.5
2  oranges 10     0        0.0
3    pears 10     5        0.5

要查看合并映射到SQL连接的概述，请参阅How to join (merge) data frames (inner, outer, left, right)?

如何使用R中不同data.frame的值更新摘要data.frame字段？

1 个答案: