I have a data.frame which looks like this (in reality 1M rows):
我有一个看起来像这样的data.frame（实际上是1M行）：
`> df
`> df
R.DMA.NAMES quarter daypart allpersons.imp rate station spot.id
1 Wilkes.Barre.Scranton.Hztn Q22014 afternoon 0.0 30 WSWB 13048713
2 Nashville Q12014 primetime 0.0 50 COM NASHVILLE 11969260
3 Seattle.Tacoma Q12014 primetime 6.1 51 ESPN SEATTLE, EVERETT ZONE 11898905
4 Jacksonville Q42013 late fringe 2.3 130 Jacksonville WAWS 11617447
5 Detroit Q22014 overnight 0.0 0 WKBD 12571421
6 South.Bend.Elkhart Q42013 primetime 11.5 325 WBND 11741171`
dput(df)
dput（DF）
structure(list(R.DMA.NAMES = c("Wilkes.Barre.Scranton.Hztn",
"Nashville", "Seattle.Tacoma", "Jacksonville", "Detroit", "South.Bend.Elkhart"
), quarter = structure(c(3L, 1L, 1L, 6L, 3L, 6L), .Label = c("Q12014",
"Q22013", "Q22014", "Q32013", "Q32014", "Q42013"), class = "factor"),
daypart = c("afternoon", "primetime", "primetime", "late fringe",
"overnight", "primetime"), allpersons.imp = c(0, 0, 6.1,
2.3, 0, 11.5), rate = c(30, 50, 51, 130, 0, 325), station = c("WSWB",
"COM NASHVILLE", "ESPN SEATTLE, EVERETT ZONE", "Jacksonville WAWS",
"WKBD", "WBND"), spot.id = c(13048713L, 11969260L, 11898905L,
11617447L, 12571421L, 11741171L)), .Names = c("R.DMA.NAMES",
"quarter", "daypart", "allpersons.imp", "rate", "station", "spot.id"
), row.names = c(NA, -6L), class = "data.frame")
I am using a ddply function to perform a calculation:
我正在使用ddply函数来执行计算：
ddply(df, .(R.DMA.NAMES, station, quarter), function (x) {
cpi = sum(df$rate) / sum(df$allpersons.imp)
})
This creates a new data.frame which looks like this:
这将创建一个新的data.frame，如下所示：
R.DMA.NAMES station quarter V1
1 Detroit WKBD Q22014 NaN
2 Jacksonville Jacksonville WAWS Q42013 56.521739
3 Nashville COM NASHVILLE Q12014 Inf
4 Seattle.Tacoma ESPN SEATTLE, EVERETT ZONE Q12014 8.360656
5 South.Bend.Elkhart WBND Q42013 28.260870
6 Wilkes.Barre.Scranton.Hztn WSWB Q22014 Inf
What I'd like to do is create a new column called "cpi" in my original df i.e. the applicable "cpi" value should appear against the particular row. Of course, the same value will repeat many times i.e. 8.36 will appear for every row which contains "Seattle.Tacoma" for R.DMA.NAMES, "ESPN SEATTLE, EVERETT ZONE" for station and Q12014 for quarter. I tried several things including:
我想要做的是在我的原始df中创建一个名为“cpi”的新列，即适用的“cpi”值应该出现在特定的行上。当然，相同的值将重复多次，即包含R.DMA.NAMES的“Seattle.Tacoma”，车站的“ESPN SEATTLE，EVERETT ZONE”和季度的Q12014的每一行都会出现8.36。我尝试了几件事，包括：
transform(df, cpi = ddply(df, .(R.DMA.NAMES, station, quarter), function (x) {
cpi = sum(df$rate) / sum(df$allpersons.imp)
})
But this didn't work ! Can someone explain . .
但这没用！有人可以解释一下。
1 个解决方案
#1
1
Use transform within ddply:
在ddply中使用transform：
ddply(df, .(R.DMA.NAMES, station, quarter),
transform, cpi = sum(rate) / sum(allpersons.imp))
#1
1
Use transform within ddply:
在ddply中使用transform：
ddply(df, .(R.DMA.NAMES, station, quarter),
transform, cpi = sum(rate) / sum(allpersons.imp))