Query¶

TypeError: unhashable type¶

Pandas query error: TypeError: unhashable type: 'numpy.ndarray'

• Caused by numexpr package, the default engine.

• Can change engine to: df.query('', engine='python'), but not efficient.

• Best to indicate using the python semantics: df.query('', parser='python') - not always work.

& vs and¶

https://stackoverflow.com/questions/21415661/logical-operators-for-boolean-indexing-in-pandas

& in pandas and numpy is element-wise logical-and while and only works for two boolean values.