ggplot2直方圖binwidth

Question

我想創建多個直方圖在一個繪圖（使用facet_wrap）。 這可能是一個示例代碼：

df <- data.frame(p1 = rnorm(100,5,2), p2 = rnorm(100,80,20), group = rep(LETTERS[1:4],25)) 

library(ggplot2) 
library(reshape) 

plotData <- melt(df, id.vars = "group", measure.vars = c("p1","p2") ) 

m <- ggplot(plotData, aes(x = value, color = group, fill = group, group = group)) 
m <- m + geom_bar(position=position_dodge()) 
m <- m + facet_wrap(~ variable,scales = "free_x") 
print(m) 

現在，我想修改它每參數創建情節（「P1」，P2" ）讓我們說10檔

截至目前，。我無法找到一個方法來做到這一點作爲binwidth /符計算應該依賴於數據的一個子集。

是否有可能呢？

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，我想分享我的解決辦法由可能延長（從上面鏈接的回答問題採取了）疊加使用縮放到直方圖計數密度曲線直方圖：

df <- data.frame(p1 = rnorm(1000,5,2), p2 = rnorm(1000,80,20), group = rep(LETTERS[1:4],25)) 

library(ggplot2) 
library(reshape) 
library(plyr) 

plotData <- melt(df, id.vars = "group", measure.vars = c("p1","p2") ) 

nBins <- 10 

groupedData <- dlply(plotData, .(variable)) 
groupedBinWidth <- llply(groupedData, .fun = function(data, nBins) { 
    r <- range(data$value, na.rm = TRUE, finite = TRUE) 
    widthOfBins = (r[2] - r[1])/nBins 
    if (is.na(widthOfBins) || is.infinite(widthOfBins) || (widthOfBins <= 0)) widthOfBins <- NULL 
    widthOfBins 
}, nBins = nBins) 

densData <- dlply(plotData, .(variable, group), .fun = function(subData){ 
    param <- subData$variable[1] 
    group <- subData$group[1] 
    d <- density(subData$value) 
    bw <- groupedBinWidth[[param]] 
    data.frame(x = d$x, y = d$y * nrow(subData) * bw , group = group, variable = param) 
}) 

hls <- mapply(function(x, b) geom_bar(aes(x = value), position = position_dodge(), data = x, binwidth = b), 
       groupedData, groupedBinWidth) 

dLay <- mapply(function(data) geom_density(data = data, aes(x = x, y = y), stat = "identity", fill = NA, size = 1), 
       densData) 

m <- ggplot(plotData, aes(x = value, color = group, fill = group, group = group)) 
m <- m + hls 
m <- m + dLay 
m <- m + facet_wrap(~ variable,scales = "free") 
print(m) 

Answer 1

試試這個 - 真的很醜陋的代碼，但如果我理解你的工作正確。你可能想玩geom_density，也許刪除填充，使其更具可讀性。

nbin<- 5 
m <- ggplot(plotData, aes(x = value, color = group, fill = group, group = group)) 
m <- m + geom_histogram(data = subset(plotData, variable == "p1"), binwidth=diff(range(subset(plotData, variable == "p1")$value))/nbin) 
m <- m + geom_histogram(data = subset(plotData, variable == "p2"), binwidth=diff(range(subset(plotData, variable == "p2")$value))/nbin) 
m <- m + facet_wrap(~ variable,scales = "free_x") 
print(m)