问题
I'm trying to use display categorical levels in the x-axis of my line chart. Say I have a data frame
mydata <- data.frame(time = c("10am", "12pm", "3pm"), month = c("JAN", "JUL", "DEC"), value = 3:5)
and I want to plot value ~ time or value ~ month. I could first create a variable that puts time on a linear scale, e.g.
mydata$time_linear <- 1:3
then try to plot
library(rCharts)
p <- nPlot(value ~ time_linear, data = mydata, type = "lineChart")
p$chart(useInteractiveGuideline = TRUE)
p
but I don't know how to force the labels.
I have looked at How to set a nvd3 axis to use strings instead of numerical values ? and nvd3 line chart with string values on x-axis but am not sure how it works in the context of rCharts. It seems like one way would be to define an array in javascript with the label names and index accordingly, and another would be to define a function with a bunch of if/else statements. The former method seems more elegant but I don't know how to conjure up an array in the right scope, and the latter would involve a nasty long anonymous function in tickFormat
What's the best way to go about this?
来源：https://stackoverflow.com/questions/25120598/strings-as-tick-values-for-rcharts-nvd3-line-chart