R: ggplot set ylim with custom break

Question

I want to customize the gap (breaks) in the y axis of the plot. I tried two options.

option1: ylim(0.0,0.6) 
option2: scale_y_continuous(breaks=seq(0.0, 0.6, 0.1))

Problem with the option1 is that it breaks in every 0.2 up to limit of y axis which is 0.6. Problem with the option2 is that it gives this illusion of drastic difference between plots since it enlarge the 0.1 segment of the plot.

What I want is y-axis to be break at every 0.1 or customize it to any break while showing the max limit of the y-axix (in this case 0.0 to 0.6 but break every 0.1).

xVal = c(1,2,3,4,5,6,7,8,9,10,11,12,13,14,15)
a = c(0.18340368127959822, 0.17496531617798133, 0.16772886654445848, 0.15934821062512169, 0.15390913489444036, 0.14578798884106348, 0.14524174121702108, 0.13958093302847951, 0.1365009715515553, 0.13337340345559975, 0.12995175856952607, 0.12583603207983862, 0.12180656145228715, 0.11824179486798418, 0.11524630600365712)
b = c(0.13544353787855531, 0.11345498050033079, 0.11449834060237293, 0.10479213576778054, 0.09677430524414686, 0.091990671548439179, 0.089965934807318487, 0.088711600335474206, 0.088923403079789909, 0.087989321310275717, 0.085424600757017272, 0.08251334730889931, 0.080178280060313953, 0.077717041621392688, 0.076638743116633837)
c = c(0.087351324973658093, 0.12113308515702567, 0.11422800742900453, 0.11264309199970789, 0.11390287790920843, 0.10774426268894192, 0.10587704437111881, 0.10474954948318291, 0.10568277685778472, 0.10201545270338952, 0.09939827283775747, 0.098062403381144761, 0.094110034623398231, 0.091211408116407641, 0.089369778116029489)

library(ggplot2)
library(reshape2)

df = data.frame(xVal, a, b, c)
df.melt = melt(df, id="xVal")

problem1:

ggplot(data=df.melt, aes(x=xVal, y=value, colour=variable)) +
            geom_point() + 
            geom_line() + 
            xlab("xVal") + ylab("YValues") + xlim(1,16) +  
            ylim(0.0,0.6)

problem2:

ggplot(data=df.melt, aes(x=xVal, y=value, colour=variable)) + 
            geom_point() + 
            geom_line() + 
            xlab("xVal") + ylab("YValues") + xlim(1,16) + 
            scale_y_continuous(breaks=seq(0.0, 0.6, 0.1))

How do I customize the y-axis such that break according to a value that I specify.

Answer 1

See the below. You need to set both the breaks AND the limits. Otherwise you may not like the breaks chosen or it may zoom in on the data and not show some of your breaks.

library(ggplot2)
library(reshape2)

xVal = c(1,2,3,4,5,6,7,8,9,10,11,12,13,14,15)
a = c(0.18340368127959822, 0.17496531617798133, 0.16772886654445848, 0.15934821062512169, 0.15390913489444036, 0.14578798884106348, 0.14524174121702108, 0.13958093302847951, 0.1365009715515553, 0.13337340345559975, 0.12995175856952607, 0.12583603207983862, 0.12180656145228715, 0.11824179486798418, 0.11524630600365712)
b = c(0.13544353787855531, 0.11345498050033079, 0.11449834060237293, 0.10479213576778054, 0.09677430524414686, 0.091990671548439179, 0.089965934807318487, 0.088711600335474206, 0.088923403079789909, 0.087989321310275717, 0.085424600757017272, 0.08251334730889931, 0.080178280060313953, 0.077717041621392688, 0.076638743116633837)
c = c(0.087351324973658093, 0.12113308515702567, 0.11422800742900453, 0.11264309199970789, 0.11390287790920843, 0.10774426268894192, 0.10587704437111881, 0.10474954948318291, 0.10568277685778472, 0.10201545270338952, 0.09939827283775747, 0.098062403381144761, 0.094110034623398231, 0.091211408116407641, 0.089369778116029489)

df = data.frame(xVal, a, b, c)
df.melt = melt(df, id="xVal")

ggplot(data=df.melt,
  aes(x=xVal, y=value, colour=variable)) + geom_point() +
  geom_line() + xlab("xVal") + ylab("YValues") + xlim(1,16) + scale_y_continuous(breaks=seq(0.0, 0.6, 0.1), limits=c(0, 0.6))