EFT questions

EFT answers

• Subtract two Series with irregular and regular timestamps in pandas with interpolation
• Tricky slicing specifications on business-day datetimeindex
• How to do pandas equivalence of SQL outer join without a key
• split a numpy array both horizontally and vertically
• Find indexes of repeated elements in an array (Python, NumPy)
• Hierarchical data: efficiently build a list of every descendant for each node
• pandas - exponentially weighted moving average - similar to excel