TypeError: expected bytes, pyarrow.lib.StringArray found

user_12248373 0
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I want a result such as below by using pyarrow:

[
  {'value': 'bar', 'key': 'foo'},
  {'value': 'bar', 'key': 'foo'},
  {'value': 'bar', 'key': 'foo'}
]

Therefore I wrote the following code:

import pyarrow as pa
fields = [pa.array(['foo', 'foo', 'foo']), pa.array(['bar', 'bar', 'bar'])]
arr = pa.StructArray.from_arrays(['key', 'value'], fields)
print(arr)

But I get the following error that is related to "arr = pa.StructArray.from_arrays(['key', 'value'], fields)":

expected bytes, pyarrow.lib.StringArray found

why? How can I fix it?

pyarrow python
1 Answers

You're close, I think you just swapped the arguments.

arr = pa.StructArray.from_arrays(fields, ['key', 'value'])

Also, what you call fields are actually instances of pa.Array. There is such a thing as pa.Field so I found the name a little confusing.

As for that error, it is because it is looking at the second argument (which it expects to be a list of names (bytes)) and finding instead a list of StringArray.

user_2026940
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