Plotting two variables as lines using ggplot2 on the same graph

[rafa1]

Year  Export Import
  <chr> <chr>  <chr> 
1 2000  79     32    
2 2001  86     34    
3 2002  87     32    
4 2003  87     32    
5 2004  98     34    
6 2005  107    37 

How can I plot both export import on the same graph, with year on the x-axis, using ggplot2?

I'm sure this is very simple, but I can't find any examples out there.

Many, many thanks for your help!

[Matthias]

Have you tried it at all?
Some inspiration: Line chart | the R Graph Gallery

For your dataset it might be done like this:

df = tribble(
 ~Year, ~Export, ~Import,
 2000,  79,     32,    
 2001,  86,     34 ,   
 2002,  87,     32,    
 2003,  87,     32,    
 2004,  98,     34,    
 2005,  107,    37)


ggplot(df, aes(x = Year)) +
  #add one line for Export
  geom_line(aes(y = Export), colour = "blue") + 
  # add another line for Import
  geom_line(aes(y = Import), colour = "lawngreen") +
  theme_classic()

However, usually it is better to have the data in the so-called long format. In this case you don't have to add each line individually, but instead can just say "colour = category")

# convert the dataset to long format
df2 = pivot_longer(df,     # the dataset we want to convert 
                   -Year,  # keep column year as it is
                   names_to = "Cat", 
                   values_to = "value")
df2
# A tibble: 12 x 3
    Year Cat    value
   <dbl> <chr>  <dbl>
 1  2000 Export    79
 2  2000 Import    32
 3  2001 Export    86
 4  2001 Import    34
 5  2002 Export    87
 6  2002 Import    32
 7  2003 Export    87
 8  2003 Import    32
 9  2004 Export    98
10  2004 Import    34
11  2005 Export   107
12  2005 Import    37

ggplot(df2, aes(x = Year,
                y = value,
                colour = Cat)) + 
  geom_line() + 
  #let's add some plots, just because we can
  geom_point(size = 3.5) + 
  theme_classic() +
  scale_colour_manual(values = c("blue", "green3"))

[mariowolfjr]

I would do:

library("ggplot2")
df <- data.frame(year = c(2000, 2001, 2002, 2003, 2004, 2005), 
                 export = c(79, 86, 87, 87, 98, 107), 
                 import = c(32, 34, 32, 32, 34, 37))

ggplot(data=df, aes(x=year)) + 
  geom_line(aes(y=export), color="darkred") +
  geom_line(aes(y=import), color="steelblue")

[rafa1]

many, many thanks! but here I got the followin: "Error: mapping must be created by aes()
Run rlang::last_error() to see where the error occurred"? Any suggest? -Would appreciate.

[FJCC]

Please show your code that makes the plot and produces the error.