使用 ddply 函数获取数据框中的百分比

Question

我有这个数据框mydf

structure(list(Driver = c("Crop agriculture", "Crop agriculture", 
"Infrastructure", "Infrastructure", "Mining", "Mining", "Mixed Agriculture", 
"Mixed Agriculture", "Other land use", "Other land use", "Pasture", 
"Pasture", "Tree crops", "Tree crops", "Water", "Water"), Period = c("1990-2000", 
"1990-2005", "1990-2000", "1990-2005", "1990-2000", "1990-2005", 
"1990-2000", "1990-2005", "1990-2000", "1990-2005", "1990-2000", 
"1990-2005", "1990-2000", "1990-2005", "1990-2000", "1990-2005"
), Total = c(120328.157829121, 301821.02190182, 12829.2774726025, 
10727.4383383233, 1087.58971425679, 639.851573022215, 27213.5917382956, 
19832.3424927037, 72326.7471322223, 64524.3243532213, 1064383.44273723, 
1347648.2335736, 7814.32273630087, 7672.0730281537, 20332.6943805768, 
17504.7712037337), n = c("n = 1669", "n = 783", "n = 298", "n = 151", 
"n = 20", "n = 7", "n = 1355", "n = 925", "n = 1623", "n = 851", 
"n = 10986", "n = 6039", "n = 316", "n = 211", "n = 466", "n = 244"
)), .Names = c("Driver", "Period", "Total", "n"), class = "data.frame", row.names = c(NA, 
-16L))

我们的想法是获取每个驱动程序在此期间的百分比。我已经尝试了 ddply 函数并得到了这行代码。

Percentage<- ddply(mydf, c("Driver", "Period"), summarise,
                   percent= ((Total/sum(Total))*100))

但是，我只得到所有单元格的 100% 值。有人知道我做错了什么吗？

Answer 1

在您的调用中，当您执行 sum(Total) 时，您使用的是组的总值，当与 Total/sum(Total) 一起使用时，只需为这个data/grouping。您可以通过在 sum() 调用中使用 df$Total 来计算整个数据集的总和。使用 ddply 这将是

ddply(df, .(Driver, Period), summarise, Pct = Total/sum(df$Total) * 100)

这是 dplyr 等价物

library(dplyr)
group_by(df, Driver, Period) %>% summarise(Pct = Total/sum(df$Total) * 100)

使用 ddply 函数获取数据框中的百分比

Get percentage in a dataframe with ddply function

r

plyr

percentage