我想在函数中使用变量名作为字符串dplyr.请参阅以下示例:
df <- data.frame(
color = c("blue", "black", "blue", "blue", "black"),
value = 1:5)
filter(df, color == "blue")
它工作得很好,但我想color通过字符串来引用,类似这样:
var <- "color"
filter(df, this_probably_should_be_a_function(var) == "blue").
我很高兴,无论如何都要这样做,并且非常乐意使用易于阅读的dplyr语法.
假设我想用以下公式绘制直方图(我知道它不是最好的,但它会说明问题):
set.seed(1)
dframe <- data.frame(val=rnorm(50))
p <- ggplot(dframe, aes(x=val, y=..count..))
p + geom_bar()
它工作得很好.但是,假设由于某种原因,我们希望频率除以收件人定义的数字.我的镜头是:
k <- 5
p <- ggplot(dframe, aes(x=val, y=..count../k))
p + geom_bar()
但是我得到了这个恼人的错误:
Error in eval(expr, envir, enclos) : object 'k' not found
是否存在使用两个类似..count..变量和一些预定义变量的方法？
我在R.中有fitdistr {MASS}函数有问题.我有这个向量:
a <- c(26,73,84,115,123,132,159,207,240,241,254,268,272,282,300,302,329,346,359,367,375,378, 384,452,475,495,503,531,543,563,594,609,671,687,691,716,757,821,829,885,893,968,1053,1081,1083,1150,1205,1262,1270,1351,1385,1498,1546,1565,1635,1671,1706,1820,1829,1855,1873,1914,2030,2066,2240,2413,2421,2521,2586,2727,2797,2850,2989,3110,3166,3383,3443,3512,3515,3531,4068,4527,5006,5065,5481,6046,7003,7245,7477,8738,9197,16370,17605,25318,58524)
我想用命令将伽马分布拟合到数据:
fitted.gamma <- fitdistr(a, "gamma")
但我有这样的错误:
Error in optim(x = c(26, 73, 84, 115, 123, 132, 159, 207, 240, 241, 254, :
non-finite finite-difference value [1]
In addition: Warning messages:
1: In densfun(x, parm[1], parm[2], ...) : NaNs produced
2: In densfun(x, parm[1], parm[2], ...) : NaNs produced
3: In densfun(x, parm[1], parm[2], ...) : NaNs produced
4: In densfun(x, parm[1], parm[2], ...) : NaNs produced
所以我尝试初始化参数:
(fitted.gamma <- fitdistr(a, "gamma", start=list(1,1)))
fit.gamma对象已创建,但在打印时会产生错误:
Error …在 html 输出中添加目录的可能方法有哪些knitr::knit2html()？
我很熟悉这个markdownHTMLOptions解决方案。然而结果并不好看？对我来说，拥有这样的目录很重要，这样它在滚动时就会跟随网页，并且我可以随时导航。