library(reticulate)
pa <- import("pyarrow")
pa$array(c(1,2,3))$cast(pa$float16())
#> Error in py_call_impl(callable, dots$args, dots$keywords): ArrowNotImplementedError: No cast implemented from double to halffloat
#> 
#> Detailed traceback: 
#> File "pyarrow/array.pxi", line 277, in pyarrow.lib.Array.cast (/Users/travis/build/BryanCutler/arrow-dist/arrow/python/build/temp.macosx-10.6-intel-3.6/lib.cxx:30459)
#> File "pyarrow/error.pxi", line 85, in pyarrow.lib.check_status (/Users/travis/build/BryanCutler/arrow-dist/arrow/python/build/temp.macosx-10.6-intel-3.6/lib.cxx:8570)