orgmode - do not export example block

Question

I try to use a example block as input to babel block, I want to export babel results only, in below example, I try to add exports none to example block but it doesn't work, the example content exported to html page as well.

How can I disable example block export?

* example
#+name: input
#+begin_example :exports none
5 1 3 2 0
#+end_example

#+begin_src python :results output :eval yes :var x=input :exports results
import matplotlib.pyplot as plt
import numpy as np

x = np.array(x.split())
x = x.astype(int)
fig,ax = plt.subplots()
ax.plot(x)
plt.savefig("test.png")
#+end_src

#+RESULTS:

[[./test.png]]

Answer 1

You could put the example in a separate section and tag it noexport:

* example input                                                        :noexport:
#+name: input
#+begin_example
5 1 3 2 0
#+end_example

* example code 
#+begin_src python :results output :eval yes :var x=input :exports results
  import matplotlib.pyplot as plt
  import numpy as np

  x = np.array(x.split())
  x = x.astype(int)
  fig,ax = plt.subplots()
  ax.plot(x)
  plt.savefig("./test.png")
#+end_src

#+RESULTS:
[[file:./test.png]]

BTW, the way that you have your headers does not really work to produce a result: the code block produces no output on its stdout so :results output makes it produce an empty result. The output file is a side effect of the code block execution, so Org mode (and babel) don't know anything about it. Did you add the result by hand?

A better way to do that is to use the following header line instead:

#+begin_src python :results file link :file test.png :eval yes :var x=input :exports results
...

That tells babel to produce a link to a file named test.png, but babel does not create the file: it expects the code block to produce it.

See e.g. this Emacs SE question for more details.

Answer 2

What I do for cases like this, where I do not want the input to some src block exported, is put the input (the example block in your case) in a drawer and set the option d:nil so as to not export drawers.

* example
:input:
#+name: input
#+begin_example
5 1 3 2 0
#+end_example
:end:

Answer 3

I don't think org offers any way to exclude example blocks from exporting. A possible work-around: if you don't want the example to show up in your export, does it need to be an example? You could make it a bash code block instead:

* example

#+name: input
#+begin_src bash :exports none
echo 5 1 3 2 0
#+end_src

#+begin_src python :results output :eval yes :var x=input :exports results
import matplotlib.pyplot as plt
import numpy as np

x = np.array(x.split())
x = x.astype(int)
fig,ax = plt.subplots()
ax.plot(x)
plt.savefig("test.png")
#+end_src