Question

我有以下测试数据：

structure(list(r = c(5.44702625911984, 6.3431860464319, 2.89023592667928, 
6.66260769449341, 7.5521021076857, 5.50645078944005, 6.70001850525037, 
7.39615449137166, 5.96032231142622, 7.88929821115731, 9.45119299499902, 
6.13534105776075, 7.79397401855071, 5.24488870603935, 4.53178061905952, 
5.80573244536445, 10.1194252475799, 12.5794215385996, 7.47503723957468, 
7.8682648760597, 15.7540766770233, 14.9800818974568, 14.5672865569748, 
9.5347507057429, 18.6791666362954, 10.4588651710497, 15.2076130678251, 
10.5052588219606, 13.1314628288852, 12.8384811800557, 10.9978569438483, 
10.0197995395016, 10.1479274794689, 12.5864754383382, 10.7985399338233, 
11.1100572430765, 10.756576992292, 9.17309427876051, 10.0441987112265, 
10.0652520950654), f1 = structure(c(2L, 2L, 2L, 2L, 2L, 2L, 2L, 
2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 1L, 1L, 1L, 
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 
1L), .Label = c("H", "L"), class = "factor"), f2 = structure(c(1L, 
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 
2L, 2L, 2L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 2L, 2L, 2L, 
2L, 2L, 2L, 2L, 2L, 2L, 2L), class = "factor", .Label = c("Joe", 
"Sally"))), .Names = c("r", "f1", "f2"), row.names = c(NA, -40L
), class = "data.frame")

以下函数应该绘制点（它确实）并连接每个组的平均值（它没有）：

testFunc <- function(formula = NULL, data = NULL) {
    res <- as.character(formula[[2]])
    fac1 <- as.character(formula[[3]][2])
    fac2 <- as.character(formula[[3]][3])

    # Specify the data & aesthetics     
    p <- ggplot(data, aes_string(x = fac1, y = res, color = fac2,
        group = fac2))

    # Now add points
    p <- p + geom_point() # works fine if we stop here

    # Due to a bug in ggplot2_0.9.3, we must calc some quantities
    # and put them in a separate data frame for a new aesthetic
    avg <- aggregate(data[,res] ~ data[,fac1]*data[, fac2], data, FUN = mean)
    names(avg) <- c("factor1", "factor2", "mean")   
    p <- p + geom_line(aes_string(x = 'factor1', y = 'mean', group = 'factor2'), data = avg)
    }

当我运行它时：

ex <- testFunc(formula = r ~ f1*f2, data = td)
print(ex)

我收到此错误：

Error in eval(expr, envir, enclos) : object 'f2' not found

我似乎总是有这些范围问题，有什么建议吗？我以为我正在跟踪适当的解决方法。使用aes代替aes_string，或者不引用geom_line中的变量名称并不能解决问题。感谢。

Answer 1

当我遇到继承美学的麻烦时，我总是回去删除主要ggplot()调用中不需要的任何内容。试试这个：

testFunc <- function(formula = NULL, data = NULL) {
    res <- as.character(formula[[2]])
    fac1 <- as.character(formula[[3]][2])
    fac2 <- as.character(formula[[3]][3])

    # Now add points
    p <- ggplot() + geom_point(data = data, aes_string(x = fac1, y = res, color = fac2,
        group = fac2)) # works fine if we stop here

    # Due to a bug in ggplot2_0.9.3, we must calc some quantities
    # and put them in a separate data frame for a new aesthetic
    avg <- aggregate(data[,res] ~ data[,fac1]*data[, fac2], data, FUN = mean)
    names(avg) <- c("factor1", "factor2", "mean")   
    p <- p + geom_line(aes_string(x = 'factor1', y = 'mean', group = 'factor2'), data = avg)
    }

Answer 2

我必须进行两项更改才能使您的功能正常运行。首先，ggplot2 0.9.3（以及之前）中存在一个错误，其中aes()的评估环境默认为全局环境。解决方法：使其在调用环境（例如，函数的环境）中进行评估，使用ggplot(..., environment = environment()。

另一项更改位于最后一行，您有p <- p + geom_line(..., data=avg)。关键在于您必须从主ggplot调用中关闭美学的继承，因为您的avg数据集没有fac2列。为此，请使用geom_line(..., inherit.aes=FALSE)。

testFunc <- function(formula = NULL, data = NULL) {
  res <- as.character(formula[[2]])
  fac1 <- as.character(formula[[3]][2])
  fac2 <- as.character(formula[[3]][3])

  # Specify the data & aesthetics     
  p <- ggplot(data, aes_string(x = fac1, y = res, color = fac2, group = fac2),
    environment = environment())

  # Now add points
  p <- p + geom_point()

  # Due to a bug in ggplot2_0.9.3, we must calc some quantities
  # and put them in a separate data frame for a new aesthetic
  avg <- aggregate(data[,res] ~ data[,fac1]*data[, fac2], data, FUN = mean)
  names(avg) <- c("factor1", "factor2", "mean")   
  p + geom_line(aes_string(x = 'factor1', y = 'mean', group = 'factor2'), 
    inherit.aes = FALSE, data = avg)
}

ex <- testFunc(formula = r ~ f1*f2, data = td)
print(ex)

ggplot2内部功能与第二审美：范围问题

2 个答案: