Answers for "The truth value of a Series is ambiguous. Use a.empty, a.bool(), a.item(), a.any() or a.all()."

ValueError: The truth value of a Series is ambiguous. Use a.empty, a.bool(), a.item(), a.any() or a.all(). site:stackoverflow.com

Well pandas use bitwise & | and each condition should be wrapped in a ()

For example following works

data_query = data[(data['year'] >= 2005) & (data['year'] <= 2010)]
But the same query without proper brackets does not

data_query = data[(data['year'] >= 2005 & data['year'] <= 2010)]

The truth value of a Series is ambiguous. Use a.empty, a.bool(), a.item(), a.any() or a.all().

#Python pandas
#This NOT works
result = result[(result['var'] > 0.25) or (result['var'] < -0.25)]

#This works
result = result[(result['var']>0.25) | (result['var']<-0.25)]

==> Use: & (and), | (or)