CODEWITHSUNDEEP
rggplot2axis-labels
Richard Herron
Richard Herron

Reputation: 10112

Manually scale discrete x axis variable in ggplot2

I have a ggplot2 plot where the x axis variable is a factor, but represents different time spans in months and years (1m, 3m, 6m, 1y, 2y, 3y, 5y, 7y, 10y, 20y, and 30y -- this is a yield curve). The factor variable gives me nice labels, but even spacing. I would like the x axis spacing proportional to the time span.

I think this adjustment should come through scale_x_discrete(), but I only see an expand option. Is my only option to convert my factors to continuous variables and forego the pretty factor labels?

Here's the relevant code.

plotYieldCurve <- ggplot(data=yieldCurveSub, aes(x=variable, y=value, group=Date))
plotYieldCurve <- plotYieldCurve + geom_line(aes(linetype=factor(Date)))
plotYieldCurve <- plotYieldCurve + xlab("Maturity") 
plotYieldCurve <- plotYieldCurve + ylab("YTM") 
plotYieldCurve <- plotYieldCurve + labs(linetype="Date") 
plotYieldCurve

The dput on yieldCurveSub is as follows.

> dput(yieldCurveSub)
structure(list(Date = structure(c(14746, 16209, 16574, 14746, 
16209, 16574, 14746, 16209, 16574, 14746, 16209, 16574, 14746, 
16209, 16574, 14746, 16209, 16574, 14746, 16209, 16574, 14746, 
16209, 16574, 14746, 16209, 16574, 14746, 16209, 16574, 14746, 
16209, 16574), class = "Date"), variable = structure(c(1L, 1L, 
1L, 2L, 2L, 2L, 3L, 3L, 3L, 4L, 4L, 4L, 5L, 5L, 5L, 6L, 6L, 6L, 
7L, 7L, 7L, 8L, 8L, 8L, 9L, 9L, 9L, 10L, 10L, 10L, 11L, 11L, 
11L), .Label = c("1 mo", "3 mo", "6 mo", "1 yr", "2 yr", "3 yr", 
"5 yr", "7 yr", "10 yr", "20 yr", "30 yr"), class = "factor"), 
    value = c(0.16, 0.01, 0.02, 0.16, 0.03, 0.02, 0.23, 0.05, 
    0.07, 0.36, 0.09, 0.23, 0.81, 0.36, 0.63, 1.3, 0.79, 1.01, 
    2.2, 1.56, 1.6, 2.9, 2.09, 2.01, 3.47, 2.54, 2.27, 4.17, 
    3.11, 2.79, 4.35, 3.39, 3.05)), row.names = c(NA, -33L), .Names = c("Date", 
"variable", "value"), class = "data.frame")

Upvotes: 2

Views: 2525

Answers (1)

Hugh
Hugh

Reputation: 16099

Would treating them as numeric be acceptable?

yieldCurveSub$variable <- ifelse(grepl("mo", yieldCurveSub$variable), 
                                 as.numeric(as.character(gsub("[^0-9]", "", yieldCurveSub$variable))) / 12,
                                 as.numeric(as.character(gsub("[^0-9]", "", yieldCurveSub$variable))))

ggplot(yieldCurveSub) + 
    geom_point(aes(x = variable, y = value)) + 
    scale_x_continuous(breaks = c(1/12, 3/12, 6/12, 1, 2, 3, 5, 7, 10,20, 30),
                       labels = c("1 mo", "3 mo", "6 mo", "1 yr", "2 yr", "3 yr", "5 yr", "7 yr", 
                                  "10 yr", "20 yr", "30 yr")

Upvotes: 3

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