# Flow¶

I received the following error message when launching H2O - how do I resolve the error?

Invalid flow_dir illegal character at index 12...


This error message means that there is a space (or other unsupported character) in your H2O directory. To resolve this error:

• Create a new folder without unsupported characters to use as the H2O directory (for example, C:\h2o).
or
• Specify a different save directory using the -flow_dir parameter when launching H2O: java -jar h2o.jar -flow_dir test

How can I use Flow to export the prediction results with a dataset?

After obtaining your results, click the Combine predictions with frame button, then click the View Frame button.

How can I call Rapids expressions from Flow?

You can use the following to write a top level function and call Rapids expression from Flow:

flow.context.requestExec "expr goes here", (err, result) -> print if err then err else result
#run this once:
callRapids = (expr) -> flow.context.requestExec expr, (err, result) -> print if err then err else result
# and then you can run this several times:
callRapids 'the expr'