I have some data like the following:

A A1 12
A A2 23
A A3 AA1 1
A A3 AA2 2
B B1 2
B B2 1

Is there a way to visualize this information in ggplot? I am looking for something like this:

   |--A1---12
   |--A2---23
A--|--A3--AA1--1
      |---AA2--2

B--|--B1---2
   |--B2---1

Any suggestions?

r graph visualization hierarchical-data ggplot2
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