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using zip for transpose

On 21/02/2019 13:49, Peter Otten wrote:
> Robin Becker wrote:

> Isn't df.values a numpy array? Then try the more direct and likely more
> efficient
> df.values.tolist()
> or, if you ever want to transpose
> df.values.T.tolist()
> The first seems to achieve what your sample code does. (In addition it also
> converts the numpy type to the corresponding python builtin, i. e.
> numpy.float64 becomes float etc.)
Thanks for the pointer.

In fact we were working through all the wrong methods eg iterrows (slow) or iterating over columns which created the need for a

However, df.values.tolist() seems to create a list of row lists which is what is actually needed and it is the fastest.
So to convert df to something for reportlab table this seems most efficient


thanks again
Robin Becker