R ggplot2 x-axis not properly show

Question

My question is in the following.
here is my raw data:

type,com,year,month,value
A,CH,2016,1,0
A,CH,2016,2,0
A,CH,2016,3,0
A,CH,2016,4,0
A,CH,2016,5,0
A,CH,2016,6,0
A,CH,2016,7,0
A,CH,2016,8,0
A,CH,2016,9,453128
A,CH,2016,10,868256
A,CH,2016,11,1015080
A,CH,2016,12,650912
B,CH,2016,1,0
B,CH,2016,2,0
B,CH,2016,3,0
B,CH,2016,4,0
B,CH,2016,5,0
B,CH,2016,6,61273
B,CH,2016,7,27711
B,CH,2016,8,161780
B,CH,2016,9,48889
B,CH,2016,10,72805
B,CH,2016,11,131466
B,CH,2016,12,73756
C,CH,2016,1,0
C,CH,2016,2,0
C,CH,2016,3,0
C,CH,2016,4,0
C,CH,2016,5,0
C,CH,2016,6,0
C,CH,2016,7,0
C,CH,2016,8,2200
C,CH,2016,9,111384
C,CH,2016,10,28758
C,CH,2016,11,21161
C,CH,2016,12,0

I use it to plot a line graph with gglot2.

The code is:

test <- read.csv("test.csv", header = T)
test_list <- split(test, test$type)
Rplot <- ggplot(test_list$A, aes(x=month, y=value, col=com))+geom_line()
Rplot

My question:
how to let my x-axis to display like month(1,2,3....,12)?
and how can I combine year and month showing on x-axis at the same time.(Jan2016, Feb2016,.....) or (2016/1, 2016/2,.....)

very appreciate.

Answer 1

Create date_label column as Date class in the dataframe using ymd() from lubridate package.

library( 'lubridate' )
test_list <- lapply( test_list, function( x ) { 
  x$date_label <- ymd( paste( x$year, month.abb[ x$month ], 01, sep = "-"))
  x 
  })

Manipulate x axis using scale_x_date()

# 1. date_labels = "%Y/%m"   - 2016/01
# 2. date_labels = "%m"      - 01
# 3. date_labels = "%b %Y"   - Jan 2016        

library( 'ggplot2' )
ggplot( data = test_list$A, aes( x = date_label, y = value, color = com, group = com ) ) +
  geom_line( size = 3 ) + 
  scale_x_date(name = "month",
               date_labels = "%m", 
               date_breaks = "1 month" )

ggplot( data = test_list$A, aes( x = date_label, y = value, group = com, color = com ) ) +
  geom_line(  size = 3 ) + 
  theme( axis.text.x = element_text( angle = 45, hjust = 1 )) +
  scale_x_date(name = "month_year",
               date_labels = "%b %Y", 
               date_breaks = "1 month" )